how does the author actually prepare us for the surprise meeting of Penelope and Odysseus throughout the Odyssey?

As Odysseus bides his time in surprising his wife, we enjoy the touching scene where his nurse recognizes the scar on his thigh while washing his feet. Penelope is oblivious to what is goind on, and Odysseus urges his housekeeper and former nurse to keep quiet. The joy we see in the nurse prepares us for the meeting of husband and wife.