The word(s) "careful" appears 79 time(s) in 74 verse(s) in Quran in Muhammad Habib Shakir translation.

(41) O you who believe! be careful of (your duty to) Allah and be with the true ones.

(42) He sends down the angels with the inspiration by His commandment on whom He pleases of His servants, saying: Give the warning that there is no god but Me, therefore be careful (of your duty) to Me.

(43) And surely this your religion is one religion and I am your Lord, therefore be careful (of your duty) to Me.

(44) And he who obeys Allah and His Apostle, and fears Allah, and is careful of (his duty to) Him, these it is that are the achievers.

(45) And be careful of (your duty to) Him Who has given you abundance of what you know.

(46) And (We sent) Ibrahim, when he said to his people: Serve Allah and be careful of (your duty to) Him; this is best for you, if you did but know:

(47) Turning to Him, and be careful of (your duty to) Him and keep up prayer and be not of the polytheists

(48) O Prophet! be careful of (your duty to) Allah and do not comply with (the wishes of) the unbelievers and the hypocrites; surely Allah is Knowing, Wise;

(49) And when you said to him to whom Allah had shown favor and to whom you had shown a favor: Keep your wife to yourself and be careful of (your duty to) Allah; and you concealed in your soul what Allah would bring to light, and you feared men, and Allah had a greater right that you should fear Him. But when Zaid had accomplished his want of her, We gave her to you as a wife, so that there should be no difficulty for the believers in respect of the wives of their adopted sons, when they have accomplished their want of them; and Allah's command shall be performed.

(50) There is no blame on them in respect of their fathers, nor their brothers, nor their brothers' sons, nor their sisters' sons nor their own women, nor of what their right hands possess; and be careful of (your duty to) Allah; surely Allah is a witness of all things.