Orthodox Christians believe Jesus was sinless. They believe that in part simply because the Bible says so. In addition, the Bible doesn't merely say Jesus was sinless. Rather, there's an underlying principle: a sinner can't atone for the sins of another sinner. Therefore, the Redeemer had to be sinless.
But over and above that issue is the related question of whether Jesus could sin. Was he impeccable?
The question is somewhat ambiguous. Are we asking whether Jesus qua human could sin or whether Jesus qua divine could sin? Some might take the position that although Jesus qua human was peccable, the divine nature acted as a check on that possibility, rendering Jesus impeccable.
Some might dismiss the whole question as one of those effete conjectures that theologians haggle over when they aren't numbering angels on pinheads. There are, however, freewill theists who take the position that unless Jesus was able to sin, he couldn't truly experience temptation. There was nothing to resist.
This typically has the adult Jesus in view. Say, Jesus in the Garden of Gethsemane.
But suppose we consider the question from the standpoint of Jesus as a young child. And let's grant for the sake of argument that Jesus could sin.
It's hard to think of anything more dangerous than an almighty child. Imagine a temper tantrum magnified by omnipotence.
Children can fly into a sociopathic rage. Yet no harm usually comes of it because they are ineffectual and the murderous mood is short-lived. But if the child was omnipotent…all hell would break loose.
Now, it might be objected that, unlike the average child, Jesus was sinless. Again, though, on the hypothesis I'm exploring, Jesus could sin. Assuming that's the case, what would prevent the realization of that potential?
In the case of Jesus as an adult, or even a teenager, we can appeal to his self-restraint. That, however, assumes a level of cognitive development which young kids lack. Young kids don't have much impulse control. Little or no cognizance regarding the long-term consequences of their actions. They are in a state of diminished responsibility.
So, if Jesus was peccable, it's hard to see what would prevent a two-year-old Jesus from sinning.
I suppose we could redefine our terms by classifying sin in age-appropriate categories. What is sinful in an adult isn't necessarily sinful in a child.
But even if we grant that distinction, it doesn't rule out certain, like killing his mother or stepbrother in a childish fit of rage. We've just said that wouldn't be sinful at his tender age.
Yet I doubt Christians who espouse the peccability of Christ wish to take it even that far. Moreover, this isn't just a question of what he could do, but what he would do given what he could do.
The question at issue is whether it's consistent to say both that he was sinless and capable of sinning. For even if adulthood supplies a firewall to maintain that distinction, that assumes a process of psychological maturation which can't be retrojected back into first few years of life.
In addition, the more special you make him as a child, the less like normal children you make him, doesn't that undermine the rationale for denying that he was impeccable? The more sui generis he is, the more disanalogous temptation is for him than it is for us. So this seems to generate a dilemma for the freewill theist.