After the complaints of thirst for water of the Jewish people in the previous aliyah, in this, the third aliyah, G-D tells Moshe and Aharon to take a staff and gather the people together before a certain rock. They should speak to the rock in front of everybody, and it would give forth water. Moshe and Aharon do gather everybody, but instead of speaking to it as commanded, Moshe strikes the rock twice and it gives forth water.
G-D says to Moshe and Aharon that, since they didn't sanctify G-D in the eyes of all the Jews, they won't bring the Jews into Israel. Rashi says that had they spoken to the rock and it had brought forth water, the Jews would have reasoned that if the rock, which doesn't speak or hear nor does it require anything to exist, does what G-D wants by bringing forth water, then certainly should we. The Torah then says that these are the waters of Maribah. Rashi points out that this is what Pharaoh's astrologers saw back in Egypt when they saw that the leader of the Jews would be smitten by water, and they then decreed that all the baby boys should be thrown into the river.
