Remembering the Mila daily:

Some Poskim[1] write that in addition to the mitzvah to perform the circumcision, there is also a mitzvah to remember the circumcision daily. The purpose of this remembrance is in order so he remember that he is a servant of G-d and bears a symbol of such on his body. This will help the individual not rebel against G-d and not view himself as emancipated.

[1] Sefer Chareidim 44