John Trapp on Psalms 127:3

Verſ. 3 Lo[illegible: 1 letter] children are an heritage of the Lord] This Solomon could not but be ſenſible of. See the title of this Pſalm; eſpecially if by children are meant good children, as Prov. 18.22. by a Wife is meant a good wife. And here the poor man that hath no inheritance otherwiſe, hath one from the Lord; for ſuch are oft full of children; neither may hee wiſh, as one graceleſſe man did, that God would keep ſuch his bleſſings to himſelf, for hee had too many of them.

Is his reward] That is, his free gift; and God will be their exceeding great reward, if by their Parents prayer and good education, they prove towardly, as the Lords heritage, and as arrows in the hand, &c.