Charles Ellicott Commentary Psalms 91:1-2

"He that dwelleth in the secret place of the Most High Shall abide under the shadow of the Almighty. I will say of Jehovah, He is my refuge and my fortress; My God, in whom I trust." — Psalms 91:1-2 (ASV)

He ... I.—The particular difficulty of this psalm, its abrupt changes of person, is encountered at the beginning. A literal rendering of the text is: “He sitting in the hiding place of the Most High; In the shadow of the Almighty he lodges, I say to Jehovah, My refuge and my fortress, My God, I trust in Him.”

The change in the last clause presents no particular difficulty, as many similar instances occur. However, the transition from the third person in the first verse to the first person in the second is very awkward, and many solutions have been proposed to resolve it.

The best solution is to supply the word blessed: “Blessed is he that,” and so on. The different names for God used here should also be noted. By their accumulation, the psalmist makes the assurance doubly sure.

It would be very natural for a copyist to omit this word, due to potential confusion with the psalm’s numerical heading and the first letter of the word that now begins the psalm text.