"...real temptation could not come to Jesus from within but only from without..." - Herman Bavinck, Reformed Dogmatics, 3:315
Back in 2015 Sam Alberry and Denny Burke sat down for a Q & A Session at Boyce College engaging issues of ministry to the LGBT community. It is a very pastorally sensitive and nuanced dialogue and I am immensely appreciative of the overwhelming majority of its content. However, I think one of the problems inherent in the way Sam Alberry initially wanted to frame the issue of temptation in the dialogue is the fact that (as often is the case in this sort of discussion) he allows a great deal of equivocation with regard to the term "temptation"--especially as it appears in the Scriptural texts.
Denny Burk helpfully pointed out how we have to be extremely careful when we speak about Jesus' temptations in comparison to ours because they are of a qualitatively different character. That qualitative difference is that his temptations are χωρὶς ἁμαρτίας, without sin (Heb 4:15). That raises the question then of how our sin interfaces with the nature of our experience of temptation and what it might look like to be "tempted" and yet be sinless. Yet, none of us has the experience of temptation without sin in the exact same way as Jesus, because we are born in sin.
Alberry speaks of homosexual desire in terms of fallenness, and yet wants to say that the temptation arising from it itself is not sin. As he says in the dialogue, "My temptations come because I am fallen, but I can't repent of my fallenness..."
But fallenness is inherently a moral quality. For humans to be born "fallen" is for them to be born in iniquity and conceived in sin, to stand as the inheritor of original sin, means that by nature we are "altogether averse from that [spiritual] good, and dead in sin" (WCF 9.3). It means that we are born with an "original corruption, whereby we are utterly indisposed, disabled, and made opposite to all good, and wholly inclined to all evil..." (WCF 6:4).
This is the matrix of fallenness in which our temptations occur, but it is emphatically not the matrix in which the temptations of Christ occur. He is χωρὶς ἁμαρτίας, without sin. His virginal conception and birth under the overshadowing power of the Holy Spirit ensures that he is unimplicated in the original sin inherited from Adam and instead "holy, innocent, unstained, separated from sinners" (Heb 7:26).
Within Christ there is no inclination to evil, no aversion to spiritual good, no disability to obey the law of God. And this raises the question then of how the nature of Jesus' "temptation" interfaces with the description of temptation outlined in James 1:13-15.
When interpreting that passage and bringing it into dialogue with our understanding of Jesus' temptation, and consequently the implications we want to draw out of Jesus' experience about what it means for us to face temptation without falling into sin, there is a common tendency to lapse into a stereotypical hermeneutical trap: the word/concept fallacy.
That is to say we assume that simply because the same base Greek verb πειράζω (which nearly universally is translated as "temptation" in English versions) is used to describe Jesus' experience in places and fallen humans' experience in others, therefore that must mean that it is speaking of the exact same concept and dynamic. For instance there is an allurement to assume what is occurring in a text like Matthew 4:1 when Jesus is tempted (πειρασθῆναι) by the devil must be informed by the same dynamic of "temptation" James describes in our experience. But, as the word/concept fallacy would teach us, just because the same words are being used in both James 1:13-15 and Matthew 4:1 does not mean that their conceptual meaning is exactly the same in both occurrences. They have the same semantic domain, but the conceptual specifics and meaning of the words in each respective context is a function of their usage in context.
And so, then the question is whether or not James is describing a phenomenon of "temptation" that we can univocally cut and paste onto Jesus experience in Matthew 4.
One of the controlling ideas for how we interpret what James is getting at in James 1:14-15 is the warning James gives in James 1:13 - "Let no one say when he is tempted, 'I am being tempted by God,' for God cannot be tempted with evil, and he himself tempts no one." James is engaging in a bit of theodicy. He is warning us not to cast off the responsibility of our temptation upon God by pointing to how God's agency is not actively involved in our temptation. His point then as he moves into his statements in James 1:14-15 is that, as Dan McCartney observes, "the abilities to tempt and to be tempted are rooted in an evil capacity within the person. It is this capacity within that is of concern to James in 1:14... Things start with 'one's own desire (τῆς ἰδίας ἐπιθυμίας, tēs idias epithymias), which places responsibility firmly on the shoulders of the individual..."
James' overall point is to demonstrate that God cannot be blamed for our temptations. He is not morally implicated in them. The culpability for the experience we have arising from our internally corrupt desires (τῆς ἰδίας ἐπιθυμίας) is something for which we are responsible and not God. But that is the rub of James 1:13-15 in the context of the overall discussion presently raging about same-sex attraction. James' point is to demonstrate that fallen humans are morally culpable for their experience of "temptation" and not God. This entails the inescapable conclusion that the sort of "temptation" which he describes in James 1:14-15 is a dynamic for which we bear ethical responsibility. It is something blameworthy. The fact that it is blameworthy is what repulses James from the thought of attempting to attribute it to the action of God in James 1:13.
"Desire" (ἐπιθυμίας) in James 1:14-15, as Douglas Moo points out, "can have a neutral meaning in the NT (cf. Luke 22:15; Phil. 1:23), but the context here makes it clear that James uses it with the more typical NT sense: fleshly, illicit desire. The word often carries for us a sexual connotation (and it has this sense in the NT), but it usually has a broader meaning, including any human longing for what God has prohibited." In the dynamic of "temptation" which James describes it is of a piece with the overall process for which we ourselves bear moral responsibility and not God.
Now, it might be an attractive hermeneutical move for one to try to draw some finely parsed line in the chain of events James goes on to describe in 1:14-15 - "But each person is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death."
One might try to argue that sin doesn't come into the picture until verse 15 and that James is there describing what happens when we begin to act upon our illicit desires. Hence then and only then in the chain of events which James describes does moral culpability arise. But that is to introduce a too finely parsed technical distinction into a process James frames as a single organic movement. It seems strained and artificial to attempt to press the "conception" of which James' metaphorically speaks in v. 15 into a moment in which we self-consciously begin to act upon a desire. As Dan McCartney observes, "...James is interested not in developing a precise theory of evil, but in making it clear that the processes of sin do not originate with God (and, subordinately, in warning of the danger of allowing the deadly chain of events to start)."
Drawing some artificial line of sudden moral accountability in the organic chain of events in which our illicit desires lures us, conceive, give birth to sin, and then fully mature into death, not only seems to press the metaphorical description of James too far, but it also ignores the reason for which James initiated his description of this chain of events. That reason is to show how God cannot be morally culpable for our temptations. He is not blameworthy for them. We are.
All of this leads to one inescapable conclusion: this cannot describe Jesus' experience of temptation. Jesus experiences nothing for which he is blameworthy. The "temptation" of Jesus in places like Matthew 4:1 may bear similarities to our experience, but just because the same word is used there by Matthew as is used by James, does not entail that the same experiential dynamic James outlines is present in Jesus in the wilderness. To assume that such is the case is to commit the word/concept fallacy. The concept of "temptation" in Matt. 4:1 must bear a qualitatively different nature than the concept of "temptation" at play in James 1:14-15. That is so because, whatever we might say about Jesus' temptation, it must be one leaves Jesus blameless at the end. But, James' point is that the process of temptation which we experience, as he describes it, is one for which we bear the blame and not God.
James seems to be describing the experience of "temptation" that occurs for those who are internally inclined to evil, that is those who either are enslaved to the corruption of original sin, or who are regenerate yet still are battling the remnants of it. Jesus has no such internal inclination as he is not the inheritor of original sin. We must conclude instead that his experience of πειρασμός or "temptation" is more akin to what we refer when we speak of "testing," which is another common, yet overlapping meaning of the "temptation" word group in Greek.
That is to say, Jesus' experience of "temptation" is a "testing" of what he will do. It is a trial into which he is placed in order for him to demonstrate his obedience. It is not by any means an experience in which he is inclined and internally lured by illicit desire. Rather, it is a moment in which his impeccable purity of heart is manifest and proven by means of external trial. Consequently, the sinlessness of Jesus in the face of "temptation" (Heb. 4:15) by no means entails the conclusion that our internal enticement and desire to do that which is unlawful is something for which we do not bear moral culpability. At the intersection of our original sin and our temptations, our temptations become fundamentally different things from Jesus' temptations.
As the Reformation has affirmed against Rome, the impact of the fall upon our desires is not just a matter of creating a disordered concupiscence among them that remains morally neutral until we act upon them, but rather that our desires themselves come with moral culpability at times. That point of difference in the debate over same-sex attraction has been helpfully outlined here.To that point I will close with an excerpt of Calvin:
"It is unnecessary to spend much time in investigating the sentiments of ancient writers. Augustine alone may suffice, as he has collected all their opinions with great care and fidelity. Any reader who is desirous to know the sense of antiquity may obtain it from him. There is this difference apparently between him and us, that while he admits that believers, so long as they are in the body, are so liable to concupiscence that they cannot but feel it, he does not venture to give this disease the name of sin. He is contented with giving it the name of infirmity, and says, that it only becomes sin when either external act or consent is added to conception or apprehension; that is, when the will yields to the first desire. We again regard it as sin whenever man is influenced in any degree by any desire contrary to the law of God; nay, we maintain that the very gravity which begets in us such desires is sin. Accordingly, we hold that there is always sin in the saints until they are freed from their mortal frame, because depraved concupiscence resides in their flesh, and is at variance with rectitude. Augustine himself dose not always refrain from using the name of sin, as when he says, 'Paul gives the name of sin to that carnal concupiscence from which all sins arise. This in regard to the saints loses its dominion in this world, and is destroyed in heaven.' In these words he admits that believers, in so far as they are liable to carnal concupiscence, are chargeable with sin."
 The discussion of temptation starts at around 12:10 in the video.
 Dan McCartney, James (BECNT), (Grand Rapids, MI: Baker, 2009), pg. 106.
 Douglas Moo, The Letter of James (PNTC), (Grand Rapids, MI: Eerdmans, 2000), pg. 74.
 McCartney, James, pg. 106.
 John Calvin, Institutes 3.3.10.