Deuteronomy 8 · a question people ask
The LORD tested Israel "to know what was in your heart" (8:2). Didn't he already know?
The verse gives the purposes together: "that he might humble you, to test you, to know what was in your heart, whether you would keep his commandments or not" (8:2). Elsewhere the Bible says plainly that the LORD knows the heart: "the LORD looks at the heart" (1 Samuel 16:7), and "I, the LORD, search the mind. I try the heart" (Jeremiah 17:10). Christians read "to know" in 8:2 in two main ways, and the two are not exclusive. Both agree that the LORD knows every heart, and that the testing was for Israel's good, "to do you good at your latter end" (8:16).
How Christians read it
Where Christians differ, Favor sets out the main views side by side and doesn't pick one.
Made known to Israel
Those who hold this view look at the next verses. In Hebrew, "that he might teach you" (8:3) is the same verb as "to know" in 8:2, in the form Brown-Driver-Briggs gives as "make known, declare", and "You shall consider in your heart" (8:5) is the same verb again. They read the test as showing Israel what was in their own heart.
Deuteronomy 8:2-3 · Deuteronomy 8:5
Known in what they did
Those who hold this view read "to know" as the LORD knowing the heart as it is shown in action, "whether you would keep his commandments or not" (8:2), as when he said to Abraham after the test, "now I know that you fear God, since you have not withheld your son, your only son, from me" (Genesis 22:12). They hold this together with his knowing all things: "LORD, you have searched me, and you know me" (Psalm 139:1).
Deuteronomy 8:2 · Genesis 22:1 · Genesis 22:12 · Psalm 139:1
The verses
“You shall remember all the way which the LORD your God has led you these forty years in the wilderness, that he might humble you, to test you, to know what was in your heart, whether you would keep his commandments or not.”
“But the LORD said to Samuel, “Don’t look on his face, or on the height of his stature, because I have rejected him; for I don’t see as man sees. For man looks at the outward appearance, but the LORD looks at the heart.””
““I, the LORD, search the mind. I try the heart, even to give every man according to his ways, according to the fruit of his doings.””
“who fed you in the wilderness with manna, which your fathers didn’t know, that he might humble you, and that he might prove you, to do you good at your latter end;”