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

(31) Lawful to you is the game of the sea and its food, a provision for you and for the travellers, and the game of the land is forbidden to you so long as you are on pilgrimage, and be careful of (your duty to) Allah, to Whom you shall be gathered.

(32) Say: The bad and the good are not equal, though the abundance of the bad may please you; so be careful of (your duty to) Allah, O men of understanding, that you may be successful.

(33) This is more proper in order that they should give testimony truly or fear that other oaths be given after their oaths; and be careful of (your duty to) Allah, and hear; and Allah does not guide the transgressing people.

(34) When the disciples said: O Isa son of Marium! will your Lord consent to send down to us food from heaven? He said: Be careful of (your duty to) Allah if you are believers.

(35) And that you should keep up prayer and be careful of (your duty to) Him; and He it is to Whom you shall be gathered.

(36) They ask you about the windfalls. Say: The windfalls are for Allah and the Apostle. So be careful of (your duty to) Allah and set aright matters of your difference, and obey Allah and His Apostle if you are believers.

(37) O you who believe! If you are careful of (your duty to) Allah, He will grant you a distinction and do away with your evils and forgive you; and Allah is the Lord of mighty grace.

(38) Eat then of the lawful and good (things) which you have acquired in war, and be careful of (your duty to) Allah; surely Allah is Forgiving, Merciful.

(39) Except those of the idolaters with whom you made an agreement, then they have not failed you in anything and have not backed up any one against you, so fulfill their agreement to the end of their term; surely Allah loves those who are careful (of their duty).

(40) How can there be an agreement for the idolaters with Allah and with His Apostle; except those with whom you made an agreement at the Sacred Mosque? So as long as they are true to you, be true to them; surely Allah loves those who are careful (of their duty).