Verses with the word strengtheneth in the Old Testament (6 verses):

Job 15:25
For he stretcheth out his hand against God, and strengtheneth himself against the Almighty.

Psalms 104:15
And wine that maketh glad the heart of man, and oil to make his face to shine, and bread which strengtheneth man's heart.

Proverbs 31:17
She girdeth her loins with strength, and strengtheneth her arms.

Ecclesiastes 7:19
Wisdom strengtheneth the wise more than ten mighty men which are in the city.

Isaiah 44:14
He heweth him down cedars, and taketh the cypress and the oak, which he strengtheneth for himself among the trees of the forest: he planteth an ash, and the rain doth nourish it.

Amos 5:9
That strengtheneth the spoiled against the strong, so that the spoiled shall come against the fortress.