The “secret place" in Psalm 91 refers to the Lord's shelter. The “shelter” being referred to in the first verse is (actually) a ‘fortress’ or a ‘tower.’ The Jerusalem Bible states as follows: “If you live in the shelter of Elyon (High), and make your home in the shadow of Shaddai (God), you can say to Yahweh: My refuge, may fortress, my God in whom I trust!" Amen.