What does Psalm 44:21 mean?

In the Old Testament, God warned Israel not to worship other gods (Exodus 20:2–3). When He brought victory to Israel, it was during their times of obedience (Psalm 44:1–8). When they sinned, God brought punishment and consequences (Judges 2:16–23). Here, the psalmist continues to reject any claim that Israel was, in his day, committing such sins (Psalm 44:17–19). His angst comes from Israel's recent humiliation and defeat (Psalm 44:9–16). To the writer, this is unjustified. In his view, God would have known—and, presumably, pointed it out—if the nation was engaged in sin (Psalm 44:20).

In at least one sense, the psalmist's claim is exactly right. Nothing is hidden from the Lord. Proverbs 5:21 says that "a man's ways are before the eyes of the LORD, and he ponders all his paths." Hebrews 4:13 affirms: "And no creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account." The psalmist also knew that the Lord knows the secrets of the heart. The book of Joshua unfolds the story of Achan. He coveted items from Jericho that the Lord had put off limits. He thought he could secretly conceal his sin by burying the items in his tent, but his sin was not hidden from the Lord. He told Joshua that Israel had sinned by taking some of the devoted things and hiding them among their own belongings (Joshua 7:10–11).

Whether it was true that Israel was innocent of such sins, when this psalm was written, is harder to say. The psalmist is certainly convinced. Therefore, he struggles to accept the suffering which the nation experiences.