The psalmist, in 119:73 knows that God’s hands have “firmed him up” — the way the sun is “fixed” in the sky at midday, the way pillars hold up the building, and the way a king has been established on his throne. Why does the psalmist care that God’s hands have firmed him — established him?
Because it is the Lord who established him, the Lord can give him understanding to learn the mitzvot, commandments. The connection is important: What the Lord makes is made for a purpose.
The Lord has fashioned us to to know and do his will. This is what we were made to do. Humans are at their best when doing what they were designed to do.