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

Judges 9:31
And he sent messengers unto Abimelech privily, saying, Behold, Gaal the son of Ebed and his brethren be come to Shechem; and, behold, they fortify the city against thee.

Nehemiah 4:2
And he spake before his brethren and the army of Samaria, and said, What do these feeble Jews? will they fortify themselves? will they sacrifice? will they make an end in a day? will they revive the stones out of the heaps of the rubbish which are burned?

Isaiah 22:10
And ye have numbered the houses of Jerusalem, and the houses have ye broken down to fortify the wall.

Jeremiah 51:53
Though Babylon should mount up to heaven, and though she should fortify the height of her strength, yet from me shall spoilers come unto her, saith the LORD.

Nahum 2:1
He that dasheth in pieces is come up before thy face: keep the munition, watch the way, make thy loins strong, fortify thy power mightily.

Nahum 3:14
Draw thee waters for the siege, fortify thy strong holds: go into clay, and tread the morter, make strong the brickkiln.