Exodus 17:2
So they quarreled with Moses and said: give us water to drink. Moses replied: why do you quarrel with me? Why do you put the Lord to the test? The quarrel — a legal dispute, rib in Hebrew — is more formal than ordinary grumbling. The people are bringing a case against Moses, demanding water as a legal right. Moses redirects the dispute immediately: why do you put the Lord to the test? The testing of God — challenging Him to prove His presence and power — is the theological dimension of what appears to be a practical complaint. Psalm 95:8–9 says do not harden your hearts as you did at Meribah, as you did that day at Massah in the wilderness, where your ancestors tested me. The naming of this incident in Psalm 95 shows that the quarrel at Rephidim became a paradigmatic case study in Israel's relationship with God: the moment when thirst became challenge became testing.