'Prime' in the Bible

Then you are to attack every fortified city and every significant city. Cut down every significant tree, fill in all of the water springs, and ruin every prime piece of land with stones."

like when I was in my prime and God trusted me with his secrets!

We live for 70 years, or 80 years if we're healthy, yet even in the prime years there are troubles and sorrow. They pass by quickly and we fly away.

Banish sorrow from your heart, and evil from your body, since both childhood and the prime of life are pointless.

I said, "Must I leave in the prime of my life? Must I be consigned to the control of Sheol? Bitter are my years!"