There's almost nothing in the gospels about circumcision. Jesus was circumcised. There's one appearance besides that, I believe, and it's almost a side issue to a much more specific discussion about something else. Jesus didn't seem very interested in it. That's interesting for a number of reasons, but I want to suggest one thing that we should conclude that may not be as obvious.
A number of modern scholars seek to explain most of the material in the gospels, particular Matthew, Luke, and especially John, as later developments in Christian thought that don't trace back to Jesus, with the evangelists placing these words in Jesus' mouth in order to give them more authority. In Matthew in particular, they frequently will find something Jesus is saying as being more about the situations Christians were facing with Pharisees in the post-70 Jewish world without a sacrificial system. The key distinctive of Jews without the sacrificial system was a distinctive beforehand, but it became even more significant after the temple was destroyed. That distinctive is circumcision.
Why do the gospels contain so little about circumcision? If this view of modern scholars is correct, and the gospels are primarily about what Christians and non-Christian Jews were fighting over post-70, then wouldn't circumcision play a great role in the gospels? Or is it rather that the gospels more accurately reflect Jesus' own concerns in his own time, and he just wasn't all that concerned with circumcision? There are many other reasons to reject (or at least be skeptical about) the view that the gospels are really about concerns that came much later, but I think this one alone is almost decisive against it.