The word(s) "strengthens" appears 3 time(s) in 3 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) Indeed there was a sign for you in the two hosts (which) met together in encounter; one party fighting in the way of Allah and the other unbelieving, whom they saw twice as many as themselves with the sight of the eye and Allah strengthens with His aid whom He pleases; most surely there is a lesson in this for those who have sight.

(2) And whenever a chapter is revealed, there are some of them who say: Which of you has it strengthened in faith? Then as for those who believe, it strengthens them in faith and they rejoice.

(3) Muhammad is the Apostle of Allah, and those with him are firm of heart against the unbelievers, compassionate among themselves; you will see them bowing down, prostrating themselves, seeking grace from Allah and pleasure; their marks are in their faces because of the effect of prostration; that is their description in the Taurat and their description in the Injeel; like as seed-produce that puts forth its sprout, then strengthens it, so it becomes stout and stands firmly on its stem, delighting the sowers that He may enrage the unbelievers on account of them; Allah has promised those among them who believe and do good, forgiveness and a great reward.