In the Believer’s Bible Commentary, William MacDonald begins his comments on Psalm 91 by telling of a five-year-old boy who was dying of diphtheria in 1922. As his mother turned her back so she could not see him take his last breath, her brother-in-law knocked at the door. He said, “I’ve come just to tell you that you don’t have to worry about the child. He is going to recover, and God is going to save his soul.” He then explained that the Lord gave him this assurance as he read Psalm 91.
MacDonald, the author of the commentary, was that dying boy. God spared his life. Thirteen years later, God saved him. And for many decades, God used him to preach and write the gospel. MacDonald labeled his comments on Psalm 91 as “My Psalm.” He stated his willingness to share the psalm, but insisted that it was his psalm. So it is with every believer who knows what it is to live in the protective custody of God.
An ‘orphan’ messianic psalm
Psalm 91 is one of the so-called “orphan psalms.” We do not know the author of this psalm. The Septuagint ascribes it to David, while others ascribe it to Moses, but no one knows for sure.
Likewise, we do not know the occasion that prompted the writing of this psalm. Nothing in the psalm points to its historical background. Even the structure of this psalm is somewhat hard to ascertain, as multiple voices apparently speak in this psalm. Yet the message of Psalm 91 is clear: the Lord will protect the one who trusts in him.