I think that it is agreed here, that, whether we hold to the view that Jesus was "not able to sin", or, "able not to sin", that the main point here ought no to be missed, that He was completely without sin. I say this, because there are some (I don't know if there are any on this board) who might fall into the error, that the human nature of Jesus, in that it was "like unto ours", was also "fallen". This is heresy, and must be condemned as so.
It is very important to know what Scripture teaches on these vital issues. And I will give but one important passage to give some light on this.
Romans 8:3:
"For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh"
The last sentence in the Greek is very important:
"katekrine ten hamartion en tei sarki" = "condemned sin in the flesh"
Had Paul repeated the article, "ten" before "en tei sarki", this would have located "sin" in the "flesh of Jesus Christ", and therefore made Jesus as sinner as we are. However, as it stands in the Greek, the phrase, "en tei sarki" modifies the verb, "katekrine", so that the "condemnation" of sin that was "placed" in Jesus' "flesh", and not "sin itself" The position of the definite article in the Greek is very important. The sinlessness of the flesh (human nature) of Jesus Christ is paramount to what Paul is saying here.
Likewise, in 2 Corinthians 5:21, when Paul wrote, "huper hemon hamartian epoiesen" = "for us sin He made" (lit), it does NOT mean that on the cross Jesus became "our sin", as many in the Word of Faith Movement teach. "hamartian" (sin) here is the substantive, not the verb. Jesus did not "become a sinner" on our behalf, as "sin" here is in the abstract, as "representing" the actual "sin itself". God the Father "poieo" (made), where the use of the Greek is not the common meaning, "to cause, produce"; but, rather as used by Herodotus, with the meaning: "to consider" (see, I.83 and 6.61, etc); that is, "treated Jesus as though He had Himself committed our sins". And, in the great exchange, "considers" us to be "Righteous" because of Jesus' perfect, sinless, life.