Disobedience to God of Aaron, at the Hitting of the Rock by Moses
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Numbers 20:23, 24
And at Mount Hor, near the border of the land of Edom, the LORD said to Moses and Aaron, / “Aaron will be gathered to his people; he will not enter the land that I have given the Israelites, because both of you rebelled against My command at the waters of Meribah.