Moses also wanted God to display His majesty or splendor to His servants. He may have meant the splendor that God would demonstrate by extending mercy to them. When the Israelites saw God"s work of showing mercy they could proceed with their work knowing that God would bless it. Even though their lives would be brief, they could derive some pleasure from their work knowing that God would give it some relative permanence. [source][source][source]
We might title this Psalm , "Reflections on the Brevity of Life." Life is short because we are sinners. Even the most godly person dies eventually (except for Enoch, Elijah, and Christians alive at the Rapture). God removed the guilt of our sins when Jesus Christ died on the cross. He imputes the effects of that work to a person when he or she trusts in Christ as Savior. However, the consequences of sin still follow. Chief among these is physical death. Nevertheless God extends His mercy to humankind and allows us to live as long as we do. His mercy enables us to enjoy life and make a profitable contribution to our world. [source][source][source]