The most important word in Psalm 91 is the little word “my.” Here, the Psalmist declares, “The Lord is my refuge and my fortress.” It is one thing to say that the Lord is a refuge and a fortress, but another thing altogether to say that “He is my refuge and my fortress” in whom “I trust.” Only the latter provides us with the essence of true consolation. The former is merely the acknowledgement of a consolation that exist, but has not been personally appropriated. 

You may admit that a fortress is formidable and impressive, but if you refuse to trust in it for your shelter and to live in it for your protection it provides you with neither refuge nor safety. It is only those who “trust” in God who are assured of His sovereign safekeeping. It is only those who choose to live in constant communion with God, as we learned from verse 1, who dwell and abide securely under the safe shelter of His shadow.

As it is with human fortresses, so it is with the divine fortress, only those who continuously dwell within it are assured of its perpetual protection. To leave the protective walls of a fortress is to expose oneself to external dangers. Likewise, to step outside of God’s will or the parameters of God’s Word, is to break your fellowship with God and to put yourself outside of His protection. We must therefore keep a constant vigil on our daily obedience to God so that we can assure ourselves of His daily protection of us. Of course, when we sin, we must immediately confess our sin (1 John 1:9). By doing so, we will immediately receive God’s forgiveness, be restored to our fellowship with Him, and find ourselves back safely inside His impregnable fortress.