Go to your bosom; Knock there, and ask your heart what it doth know.

Don't judge a man's conscience by looking at his face cause he may have a bad heart.

One may smile, and smile, and be a villain.

One's own self is well hidden from one's own self; of all mines of treasure, one's own is the last to be dug up.

After coming into contact with a religious man I always feel I must wash my hands.

Talking much about oneself can also be a means to conceal oneself.