Moses continues to tell the people of Israel Yahweh's words as if the Israelites are one person. He tells them what they should tell their children about Yahweh's commandments. (See: [[rc://en/ta/man/translate/figs-you]])
The word "this" refers to keeping Yahweh's commands. This is a metonym for Yahweh considering them righteous. AT: "he will consider us righteous" (See: [[rc://en/ta/man/translate/figs-metonymy]])