Reading Psalm 90 This morning. I think a key to understanding and relating to this Psalm is seeing that it is a Psalm of Moses...
"A Prayer of Moses, the man of God. Lord, you have been our dwelling place in all generations. Before the mountains were brought forth, or ever you had formed the earth and the world, from everlasting to everlasting you are God. You return man to dust and say, 'Return, O children of man!' For a thousand years in your sight are but as yesterday when it is past, or as a watch in the night. You sweep them away as with a flood; they are like a dream, like grass that is renewed in the morning: in the morning it flourishes and is renewed; in the evening it fades and withers. For we are brought to an end by your anger; by your wrath we are dismayed. You have set our iniquities before you, our secret sins in the light of your presence. For all our days pass away under your wrath; we bring our years to an end like a sigh. The years of our life are seventy, or even by reason of strength eighty; yet their span is but toil and trouble; they are soon gone, and we fly away. Who considers the power of your anger, and your wrath according to the fear of you? So teach us to number our days that we may get a heart of wisdom. Return, O LORD! How long? Have pity on your servants! Satisfy us in the morning with your steadfast love, that we may rejoice and be glad all our days. Make us glad for as many days as you have afflicted us, and for as many years as we have seen evil. Let your work be shown to your servants, and your glorious power to their children. Let the favor of the Lord our God be upon us, and establish the work of our hands upon us; yes, establish the work of our hands!" - Psalms 90:1-17 ESV
Moses is so systematic and structured... counting and measuring... affliction and work. The prayer of the man of the Law is, 'Establish the work of our hands!'. Moses lead the children of Israel through the desert as nomads... the work of their hands was never established. As soon as they got settled somewhere the pillar of cloud moved and they had to pack up and start over somewhere else. Amazing.
When the children of Israel crossed the red sea they were saved but they wandered until they crossed over the Jordan river. The Jordan river talks about co-Crucifixion. Moses could not go with them. It could not be law and counting and structure. Now it would be Joshua. The man who had a different spirit. A taker of what was given. A warrior. Not a structured scholar but a simple believer. A man of mission. Both men are types of Christ but Christ is the substance.
"And Jesus came and said to them, 'All authority in heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.' " - Matthew 28:18-20 ESV
The substance is grace. Grace had to come directly from the source. We see grace in men in the old testament... David especially... but Christ writes his words directly on our hearts. The work of our hands will never be established wandering in the wilderness... the work can and has been established by Jesus Christ... passing over Jordan and into the promised land we begin to take what God has already given us.