"Look both ways before crossing the street," Jim said sternly, clapping the kid on the shoulder. "And don't take any candy from strangers, okay?" It's teasing, but the sentiment is clear enough, and Chekov knows him well enough to parse his meaning from the words. It's not Jim being condescending in the least - he knows, has seen what this kid can do. But Jim does worry about him. He's not the same kid he was back at the academy, but damnit. Captain's prerogative.