A good sermon on Psalm 91 comes from the Calvin Institute of Christian Worship, and it speaks on the protection a Christian believer can have from trusting in God. Another sermon comes from Irish pastor David Legge, who writes about how God brings believers through troubled times.
Psalm 91 is considered a devotion of comfort and trust. It consists of two main sections. The first section speaks of a believer's trust in God, while the second focuses on God's promise of deliverance. The Psalmist describes God's protection of His people and how He is with those who abide in Him.
The sermon from the Calvin Institute of Christian Worship establishes a theme of God's protection of a believer through the pitfalls of life. It also calls upon the pastor giving the sermon to explain the meaning of the phrase “to take refuge in God." The pastor may compare and contrast opposites, such as depending on political alliances, lies or idols.
David Legge's sermon on Psalm 91 follows a similar structure, but makes the distinction that God being with a believer in times of troubles does not mean the believer's troubles can be wholly avoided. The sermon ends with a prayer thanking God for His protection and asking for His help in trusting His word through troubles.