Genesi 25:20

And Isaac was forty years old when he took Rebekah to wife, the daughter of Bethuel the Syrian of Padanaram, the sister to Laban the Syrian.

Ver. 20. And Isaac was forty years old.] He was not overhasty to marry in the heat of his youth: but by hard labour, ardent prayers, and pious meditations, kept under his body, and brought it into subjection, as St Paul likewise did. 1Co 9:27 "We are not debtors to the flesh"; Rom 8:12 we owe it nothing but stripes, nothing but the blue eye, that the apostle gave it.