Traditionally, the church has believed that Jesus was completely sinless. Several passages make this clear:
For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God. (1 Corinthians 5:21)
For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin. (Hebrews 4:15)
Traditional theological teaching doesn’t just say that Jesus didn’t sin, it says that He couldn’t sin. Some Christians seem to think that Jesus could sin. He chose not to sin, but, nevertheless, it was possible for Him to. If Jesus couldn’t sin at all, then wouldn’t that render His temptations completely superfluous? What meaning did they have if Jesus couldn’t sin at all? I tackle the question of Jesus’s temptations in a previous blog, but for now I’m going to explore the question of whether Jesus could sin or not.
It’s essential that Christians hold to the complete sinlessness of Jesus; not just that He didn’t sin, but that He couldn’t sin. Let me explain why.
In philosophy, there is something called Possible World Semantics. A possible world is simply a logically possible description of the way reality could be. This world that we inhabit is the actual world. Some examples of a possible world would include one where everything is exactly how it is in the actual world, but you are sitting a few inches to the left, or one where only a frog exists, or one where there’s unicorns, etc. This philosophical tool is used to talk about possibility, impossibility, and necessity. Something that possibly exists, exists in some possible worlds, but not others (ex. dogs and unicorns). If something is impossible, it doesn’t exist in any possible world (ex. Square circles, married bachelors). If something exists necessarily, then it exists in all possible worlds because necessary things can’t not exist (ex. 2+2=4). Christians think that God necessarily exists and that His good and holy character is necessarily what it is. Keep in mind that philosophers (except maybe a rare few) don’t actually think these possible worlds exist, they’re just used for thought experiments.
Let’s use this tool to think about God’s nature and whether Jesus could sin. Christians hold that God is necessarily good. He cannot sin. Jesus Himself is God, having the very nature of God. If Jesus could sin, then there is a possible world where Jesus does sin. If this is the case, then there is a possible world where Jesus is not God, because God cannot sin. However, God is necessarily good, which means He is good in every possible world, and Jesus has the very nature of God, so Jesus couldn’t sin.
Basically, if He could sin, then he could cease to be God, but God can’t cease to be God. See the contradiction in affirming that Jesus could sin?
This is good news for us, because it means that we have a perfectly good Savior who could live the life that humans ought to live. While we stumble during our lives, He can be trusted as our firm foundation because He can never be shaken.