There is no love greater than the love of parents for their children.

There was an incident involving a man who made a will and said: My son will not inherit from me until he becomes a fool. Rabbi Yosei son of Rabbi Yehuda went to Rabbi Yehoshua ben Korha to inquire about this incident. They peered from the outside and they saw Rabbi Yehoshua ben Korha stamping on his hands and feet, with a rope of reed grass in his mouth, and he was following his son and playing with him. When they saw him, they hid themselves. When they entered his house and asked him about that incident, he began laughing and said to them: I take an oath by your lives, this incident about which you asked me just happened to me [as I just now acted like a fool]. They said to him: From here one can learn that when a person sees his children and interacts with them, it is as though he becomes a fool. (Yalkut Shimoni 2:846)