What is the significance of Deuteronomy 8:2?

Moses tells the Israelites that the Lord kept them in the desert forty years “in order to humble you, testing you to know what was in your heart, whether or not you would keep his commandments.”

In the classical view, God would have of course eternally known the character the people would develop in the desert and thus there would be no point in testing anyone. Nor could Scripture be straightforward in its explanation of the purpose of this testing (viz. “to know…”).

What is more, Psalm 95:10–11 and Hebrews 3:7–10 describe God’s disappointment in the outcome of this testing. Such disappointment is difficult to reconcile with the view that God was certain of the outcome before he created the world. Indeed, if God eternally foreknew the character of these people one wonders why he nevertheless strove with them for forty years. How can an all-wise God genuinely strive to accomplish something he foreknows will fail?

Along the same lines, we must wonder why Scripture repeatedly says that God’s Spirit is “grieved” by people who resist him (e.g. Eph. 4:30) — if indeed we believe that the Spirit eternally foreknows that his work with these people will be fruitless. So far as I can see, the authenticity of God’s striving and the reality of God’s grief depend upon the uncertainty of the outcome.