Rashi on Genesis 22:8/רש"י על בראשית כ״ב:ח׳

1יראה לו השה — this means as much as: He will look out for and choose a lamb for Himself, and if there will be no lamb for a burnt offering, then, בני MY SON will be the offering. Although Isaac then understood that he was travelling on to be slain, yet.

2וילכו שניהם יחדיו THEY WENT BOTH OF THEM TOGETHER — with the same ready heart (Genesis Rabbah 56:4).