BOOK IV   
Psalm 90 Feb. 21 A Prayer by Moses, the man of God.  1Lord, You have been our dwelling place in all generations. 2Before the mountains were brought forth, before You had formed the land and the world, even from everlasting to everlasting, You are God. 3You turn man to destruction saying, Return, you children of men. 4For a thousand years in Your sight are just like yesterday when it is past, like a watch in the night. 5You sweep them away as they sleep; in the morning they sprout like new grass. 6In the morning it sprouts and springs up; by evening, it is withered and dry. 7For we are consumed in Your anger, we are troubled in Your wrath. 8You have set our iniquities before You, our secret sins in the light of Your face. 9For all our days have passed away in Your wrath, we bring our years to an end as a sigh. 10The days of our years are seventy, or even by reason of strength eighty years; yet their pride is but labour and sorrow, for it passes quickly, and we pass away. 11Who knows the power of Your anger, Your wrath according to the fear that is due to You? 12So teach us to number our days so that we may gain a heart of wisdom. 13Relent, Yahweh! How long? Have compassion on Your servants! 14Satisfy us in the morning with Your grace, that we may rejoice and be glad all our days. 15Make us glad for as many days as You have afflicted us, for as many years as we have seen evil. 16Let Your work appear to Your servants; Your glory to their children. 17Let the grace of the Lord our God be upon us; establish the work of our hands for us; yes, establish the work of our hands.   

Commentary

90:1 There is a repeated Biblical theme that the believer's relationship with the God is essentially mutual. We dwell in God, and He dwells in us (1 Cor. 3:16). Thus "he that lives in love lives in God, and God in him " (1 Jn. 4:15,16).
90:10 This is one of many Biblical reasons for understanding the urgency of our need to devote our time to the Lord and not fritter it away. We must number our days, realize their number is only 70 years, and therefore apply our hearts unto wisdom (:10 cp. :12). "Wisdom is the principal thing; therefore get wisdom" (Prov. 4:7).
90:13 Relent- Moses several times persuaded God to change His stated purpose concerning Israel, and here once again he is trying to persuade God not to allow the rebellious generation of Israel to perish in the wilderness. The prayer wasn’t answered, but it’s a fine example of someone very intimate with God pleading with Him to change His mind.