"If Jesus could not sin then why did Satan tempt him?" This is a question that is frequently asked by the Peccability camp. I am going to make an argument that when Satan tempted Jesus he was not fully convinced that he was the Son of God. I will make this argument based on how the devil addresses Jesus before and after the wilderness temptation.
IF THOU BE THE SON OF GOD
"If thou be the Son of God," is the question Satan asked during his temptation of Christ (Matthew 4:3, 6). What does this phrase mean? We are going to examine it from two perspectives: 1. How is it used else where in scripture? 2. How does Satan address Jesus post temptation?
I will first show you how this kind of language is used in scripture. It will be clear that this phrase is used from a position of unbelief. The scoffers and unbelievers at the cross said, "If thou be the Son of God, come down from the cross (Matt 27:40)." One of the soldiers MOCKED him saying, "if thou be the king of the Jews, save thyself (Luke 23:37)." Again, one of the malefactors RAILED on him saying, "if thou be the Christ, save thyself and us (Luke 23:39)." It is clear that this type terminology is always used from a position of unbelief.
The second thing that I want to point out is how Satan's language changes from, "if thou be the Son of God," to, "I know thee who thou art," after the wilderness temptation. The devil never again says, "if thou be the Son of God," when addressing Jesus.
Notice the difference in language:
Satan's next recorded conversation with Jesus in Matthew, after the wilderness temptation, goes something like this, "what have we to do with the, Jesus, thou Son of God (Matthew 8:29)?"
After Mark's account of the wilderness temptation Satan's next recorded words to Jesus are, "Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art, the Holy One of God (Mark 1:24)."
Luke records is exactly as Mark does, "Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art; the Holy One of God (Luke 4:34)."
It appears that Satan leaves wilderness having been totally convinced that Jesus is the Son of God. Never again does he ask, "if thou be the Son of God." There was something that changed in Satan's mind after the wilderness experience. Perhaps Satan was testing Jesus as he had all of the false Christs that had came before him; he found all of those others to be weak and frail, but not this man Jesus, for had had done what no other had done, resisted the "wiles of the devil."
If you argue, "no, Satan knew exactly who he was," then the question is moot. For if Satan knew exactly who he was, then he would have also known that he would not fail (Isaiah 42:4). Tempting a Jesus that you know for sure will not fail is as equally a waste of time as tempting a Jesus that cannot fail. For all practical purposes the result is the same. So I ask, "If Satan knew Jesus would not fail, why tempt him?"