Several answers have been attributed to this question, though many not correct. Let us look to Scripture. In looking at what Jesus says in regards to the issue, look at John 5. John 5:19 says, “Truly, truly, I say to you, the Son can do nothing of his own accord, but only what he sees the Father doing. For whatever the Father does, that the Son does likewise” (ESV). Jesus could not have sinned, at all. It was not possible for Him to do so for He cannot do anything apart from God the Father, and seeing that it was sin that separated God the Father from mankind, Jesus could not have been in holy communion with the Father if He had sinned; His Being is of the “same substance” (homoousios- Gk.) as God the Father’s and the Holy Spirit’s. We see on the cross, when Jesus becomes the sin-bearer for His people, God the Father turns His back to Him (Matt. 27:46; Mark 15:34), all the while the Holy Spirit is empowering Christ to endure the wrath of the Father on the cross for sin (Sinclair Ferguson has a great explanation of the Holy Spirit’s work in Christ on the cross- may post it some time). Sin is an act that is done on an individual’s own accord. You and I sin on our own. God does not assist us in such rebellion. Naturally, as sinners (Romans 3; Ephesians 2), we do not need any help outside of our own beings to sin. Jesus never sinned (this would have disqualified Him from being the spotless Lamb slain for redemption) nor could He have sinned seeing His relationship of mimicry to the Father (John 5:19). I once heard someone say, “if Jesus could have sinned here, on earth, whose to say or how can we be assured He could not sin in heaven?” We turn to Hebrews 13:8, which says, “Jesus Christ is the same yesterday, today and forever.” Jesus could not have sinned on earth, and He cannot now in heaven for He remains our unchanged Great High Priest (Heb. 4:14). Also, let us remember that on the cross, as mentioned, Jesus bore the guilt and penalty for sin though He, Himself, was innocent.