In 1787, one of the declared objects for ordaining and establishing the Constitution was to form a more perfect Union.
Accordingly, Article XIII states that the Union "shall be perpetual"
By itself the word perpetual appears much earlier in the history of political thought. In January 44 B.C., Denarii coins were struck with the image of Julius Caesar and the Latin inscription "Caesar Dic(tator in) Perpetuo"
Psalm 27: 1-3
The LORD is my light and my salvation whom shall I fear? The LORD is the stronghold of my life-- of whom shall I be afraid? When the wicked advance against me to devour me, it is my enemies and my foes who will stumble and fall. Though an army besiege me, my heart will not fear; though war break out against me, even then I will be confident.