Deuteronomy 13:1-3 says God permits true-predicting false prophets to arise 'to know whether you indeed love the LORD your God' — implying God learns something through the test.

This is a classical anthropopathism question with a long history of careful theological treatment, closely paralleled by Genesis 22:12 ('now I know that you fear God') after Abraham's binding of Isaac. The Hebrew verb underlying 'to know' (yada) frequently denotes experiential, relational, or manifested knowledge — knowledge made evident in observable reality — rather than first-time cognitive acquisition of a previously unknown fact (compare its use for intimate experiential knowledge in Gen 4:1). Classical theism, following Augustine and developed systematically by Aquinas (Summa Theologiae I.14 on divine knowledge, and I.13 on analogical predication), treats such texts as accommodated language: Scripture speaks of God's engagement with time-bound human testing scenarios in creaturely, phenomenological terms so the moral and relational reality — Israel's loyalty being put to observable, public proof, for Israel's own benefit and the historical record — is communicated vividly, without implying that a timelessly omniscient God undergoes temporal cognitive change. Calvin's doctrine of divine accommodation makes the same move explicitly. The text's own parallel in Deuteronomy 8:2 confirms this reading: God tests Israel in the wilderness 'to know what was in your heart,' explicitly framed as formational for Israel's self-knowledge, not information-gathering for God's benefit. Reading 'know' univocally, as though the Hebrew narrative idiom and later systematic-philosophical vocabulary of omniscience occupy the same semantic register, commits an equivocation: it presses ordinary relational language into technical metaphysical service it was never designed to bear.

Divine simplicity and timeless omniscience (Aquinas, ST I.14) offer a coherent classical account on which God's knowledge is not acquired sequentially but eternally and exhaustively present to him; testing-language in Scripture is analogically, not univocally, predicated of God, which resolves the apparent tension without denying either the text's plain sense or God's perfect knowledge.