פּירוש אויף תהילים 127:3

Behold, the heritage of the Lord for that man [who banishes sleep from his eyes].

sons These are the disciples whom he sets up, who are to him like sons.

the reward is the fruit of the innards The reward is the fruit of the Torah that is in his heart as it is said (Prov. 22:18): “For it is pleasant that you guard them in your innards.”