I had to put it down. It was a book of high adventure, set during the second world war, about a daring mission to discover the identity of enemy spies. But the language got to me. Not the swearing. There wasn’t any. But the constant reference to God’s name in every variation. It jarred, and so just before the big reveal, I had to abandon mission. I felt like I was hitting the rock with a stick.

During the wilderness journey of the Israelites, the people ran short of water. It had happened once before, and on that first occasion, Moses was instructed to hit a particular rock to release water, which it did. On the second occasion, Moses was instructed to speak to the rock. But in his anger, he struck it. Water came out for the people, but God’s anger came out against Moses. And for his irreverence he was forbidden to enter the Promised Land.

When Paul tells us that the Rock was Christ, the sin of Moses becomes more scarlet, the anger of God more justified, and the refusal to grant Moses’ plea for clemency more understood: “But the Lord was angry with me because of you and would not listen to me. And the Lord said to me, ‘Enough from you; do not speak to me of this matter again.’” God takes his honour seriously, and those who strike the Rock are in danger of being struck. Which this reader needed to understand.