Moses pitched the tent of meeting outside the camp, where the pillar of cloud descended and the LORD spoke with him face to face, as a man speaks with a friend. Moses pleaded that God's presence go with Israel (Exodus 33:7-23).
7Now Moses used to take the tent and pitch it at a distance outside the camp. He called it the Tent of Meeting, and anyone inquiring of the LORD would go to the Tent of Meeting outside the camp. 8Then, whenever Moses went out to the tent, all the people would stand at the entrances to their own tents and watch Moses until he entered the tent. 9As Moses entered the tent, the pillar of cloud would come down and remain at the entrance, and the LORD would speak with Moses.
Paul quotes God's words to Moses about mercy and compassion.
What then shall we say? Is God unjust? Certainly not! For He says to Moses: “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” So then, it does not depend on man’s desire or effort, but on God’s mercy.
Exodus 33:19 records God's answer when Moses asks to see His glory. Romans 9:15 quotes the words about mercy and compassion.