Moses striking the Rock, originally uploaded by Lawrence OP.

"Tormented by thirst, the people complained against Moses. ‘Why did you bring us out of Egypt?’ they said. ‘Was it so that I should die of thirst, my children too, and my cattle?’ Moses appealed to the Lord.

‘How am I to deal with this people?” he said. ‘A little more and they will stone me!’ the Lord said to Moses, ‘Take with you some of the elders of Israel and move on to the forefront of the people; take in your hand the staff with which you struck the river, and go. I shall be standing before you there on the rock, at Horeb. You must strike the rock, and water will flow from it for the people to drink.’ This is what Moses did, in the sight of the elders of Israel. The place was named Massah and Meribah because of the grumbling of the sons of Israel and because they put the Lord to the test by saying, ‘Is the Lord with us, or not?’"

- Exodus 17:3-7, which is today's first reading for the Third Sunday of Lent.

Detail from a stained glass window in St Giles Cathedral, Edinburgh.