The word(s) "strengthen" appears 20 time(s) in 19 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) And most certainly We gave Musa the Book and We sent apostles after him one after another; and We gave Isa, the son of Marium, clear arguments and strengthened him with the holy spirit, What! whenever then an apostle came to you with that which your souls did not desire, you were insolent so you called some liars and some you slew.

(2) We have made some of these apostles to excel the others among them are they to whom Allah spoke, and some of them He exalted by (many degrees of) rank; and We gave clear miracles to Isa son of Marium, and strengthened him with the holy spirit. And if Allah had pleased, those after them would not have fought one with another after clear arguments had come to them, but they disagreed; so there were some of them who believed and others who denied; and if Allah had pleased they would not have fought one with another, but Allah brings about what He intends.

(3) 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.

(4) And if We had prescribed for them: Lay down your lives or go forth from your homes, they would not have done it except a few of them; and if they had done what they were admonished, it would have certainly been better for them and best in strengthening (them);

(5) When Allah will say: O Isa son of Marium! Remember My favor on you and on your mother, when I strengthened you I with the holy Spirit, you spoke to the people in the cradle and I when of old age, and when I taught you the Book and the wisdom and the Taurat and the Injeel; and when you determined out of clay a thing like the form of a bird by My permission, then you breathed into it and it became a bird by My permission, and you healed the blind and the leprous by My permission; and when you brought forth the dead by My permission; and when I withheld the children of Israel from you when you came to them with clear arguments, but those who disbelieved among them said: This is nothing but clear enchantment.

(6) And remember when you were few, deemed weak in the land, fearing lest people might carry you off by force, but He sheltered you and strengthened you with His aid and gave you of the good things that you may give thanks.

(7) And if they intend to deceive you-- then surely Allah is sufficient for you; He it is Who strengthened you with His help and with the believers

(8) If you will not aid him, Allah certainly aided him when those who disbelieved expelled him, he being the second of the two, when they were both in the cave, when he said to his companion: Grieve not, surely Allah is with us. So Allah sent down His tranquillity upon him and strengthened him with hosts which you did not see, and made lowest the word of those who disbelieved; and the word of Allah, that is the highest; and Allah is Mighty, Wise.

(9) 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.

(10) And all we relate to you of the accounts of the apostles is to strengthen your heart therewith; and in this has come to you the truth and an admonition, and a reminder to the believers.