• تُكَلَّفُ
• مُتَكَلِّفِين
• نُكَلِّفُ
• يُكَلِّفُ

Appears 8 times in the Quran.

1. 2:233 وَٱلْوَٰلِدَٰتُ يُرْضِعْنَ أَوْلَٰدَهُنَّ حَوْلَيْنِ كَامِلَيْنِ لِمَنْ أَرَادَ أَن يُتِمَّ ٱلرَّضَاعَةَ وَعَلَى ٱلْمَوْلُودِ لَهُۥ رِزْقُهُنَّ وَكِسْوَتُهُنَّ بِٱلْمَعْرُوفِ لَا تُكَلَّفُ نَفْسٌ إِلَّا وُسْعَهَا لَا تُضَآرَّ وَٰلِدَةٌۢ بِوَلَدِهَا وَلَا مَوْلُودٌ لَّهُۥ بِوَلَدِهِۦ وَعَلَى ٱلْوَارِثِ مِثْلُ ذَٰلِكَ فَإِنْ أَرَادَا فِصَالًا عَن تَرَاضٍ مِّنْهُمَا وَتَشَاوُرٍ فَلَا جُنَاحَ عَلَيْهِمَا وَإِنْ أَرَدتُّمْ أَن تَسْتَرْضِعُوٓا۟ أَوْلَٰدَكُمْ فَلَا جُنَاحَ عَلَيْكُمْ إِذَا سَلَّمْتُم مَّآ ءَاتَيْتُم بِٱلْمَعْرُوفِ وَٱتَّقُوا۟ ٱللَّهَ وَٱعْلَمُوٓا۟ أَنَّ ٱللَّهَ بِمَا تَعْمَلُونَ بَصِيرٌ

   And the mothers should suckle their children for two whole years for him who desires to make complete the time of suckling; and their maintenance and their clothing must be-- borne by the father according to usage; no soul shall have imposed upon it a duty but to the extent of its capacity; neither shall a mother be made to suffer harm on account of her child, nor a father on account of his child, and a similar duty (devolves) on the (father's) heir, but if both desire weaning by mutual consent and counsel, there is no blame on them, and if you wish to engage a wet-nurse for your children, there is no blame on you so long as you pay what you promised for according to usage; and be careful of (your duty to) Allah and know that Allah sees what you do.
   

2. 2:286 لَا يُكَلِّفُ ٱللَّهُ نَفْسًا إِلَّا وُسْعَهَا لَهَا مَا كَسَبَتْ وَعَلَيْهَا مَا ٱكْتَسَبَتْ رَبَّنَا لَا تُؤَاخِذْنَآ إِن نَّسِينَآ أَوْ أَخْطَأْنَا رَبَّنَا وَلَا تَحْمِلْ عَلَيْنَآ إِصْرًا كَمَا حَمَلْتَهُۥ عَلَى ٱلَّذِينَ مِن قَبْلِنَا رَبَّنَا وَلَا تُحَمِّلْنَا مَا لَا طَاقَةَ لَنَا بِهِۦ وَٱعْفُ عَنَّا وَٱغْفِرْ لَنَا وَٱرْحَمْنَآ أَنتَ مَوْلَىٰنَا فَٱنصُرْنَا عَلَى ٱلْقَوْمِ ٱلْكَٰفِرِينَ

   Allah does not impose upon any soul a duty but to the extent of its ability; for it is (the benefit of) what it has earned and upon it (the evil of) what it has wrought: Our Lord! do not punish us if we forget or make a mistake; Our Lord! do not lay on us a burden as Thou didst lay on those before us, Our Lord do not impose upon us that which we have not the strength to bear; and pardon us and grant us protection and have mercy on us, Thou art our Patron, so help us against the unbelieving people.
   

3. 4:84 فَقَٰتِلْ فِى سَبِيلِ ٱللَّهِ لَا تُكَلَّفُ إِلَّا نَفْسَكَ وَحَرِّضِ ٱلْمُؤْمِنِينَ عَسَى ٱللَّهُ أَن يَكُفَّ بَأْسَ ٱلَّذِينَ كَفَرُوا۟ وَٱللَّهُ أَشَدُّ بَأْسًا وَأَشَدُّ تَنكِيلًا

   Fight then in Allah's way; this is not imposed on you except In relation to yourself, and rouse the believers to ardor maybe Allah will restrain the fighting of those who disbelieve and Allah is strongest in prowess and strongest to give an exemplary punishment.
   

4. 6:152 وَلَا تَقْرَبُوا۟ مَالَ ٱلْيَتِيمِ إِلَّا بِٱلَّتِى هِىَ أَحْسَنُ حَتَّىٰ يَبْلُغَ أَشُدَّهُۥ وَأَوْفُوا۟ ٱلْكَيْلَ وَٱلْمِيزَانَ بِٱلْقِسْطِ لَا نُكَلِّفُ نَفْسًا إِلَّا وُسْعَهَا وَإِذَا قُلْتُمْ فَٱعْدِلُوا۟ وَلَوْ كَانَ ذَا قُرْبَىٰ وَبِعَهْدِ ٱللَّهِ أَوْفُوا۟ ذَٰلِكُمْ وَصَّىٰكُم بِهِۦ لَعَلَّكُمْ تَذَكَّرُونَ

   And do not approach the property of the orphan except in the best manner until he attains his maturity, and give full measure and weight with justice-- We do not impose on any soul a duty except to the extent of its ability; and when you speak, then be just though it be (against) a relative, and fulfill Allah's covenant; this He has enjoined you with that you may be mindful;
   

5. 7:42 وَٱلَّذِينَ ءَامَنُوا۟ وَعَمِلُوا۟ ٱلصَّٰلِحَٰتِ لَا نُكَلِّفُ نَفْسًا إِلَّا وُسْعَهَآ أُو۟لَٰٓئِكَ أَصْحَٰبُ ٱلْجَنَّةِ هُمْ فِيهَا خَٰلِدُونَ

   And (as for) those who believe and do good We do not impose on any soul a duty except to the extent of its ability-- they are the dwellers of the garden; in it they shall abide.
   

6. 23:62 وَلَا نُكَلِّفُ نَفْسًا إِلَّا وُسْعَهَا وَلَدَيْنَا كِتَٰبٌ يَنطِقُ بِٱلْحَقِّ وَهُمْ لَا يُظْلَمُونَ

   And We do not lay on any soul a burden except to the extent of its ability, and with Us is a book which speaks the truth, and they shall not be dealt with unjustly.
   

7. 38:86 قُلْ مَآ أَسْـَٔلُكُمْ عَلَيْهِ مِنْ أَجْرٍ وَمَآ أَنَا۠ مِنَ ٱلْمُتَكَلِّفِينَ

   Say: I do not ask you for any reward for it; nor am I of those who affect:
   

8. 65:7 لِيُنفِقْ ذُو سَعَةٍ مِّن سَعَتِهِۦ وَمَن قُدِرَ عَلَيْهِ رِزْقُهُۥ فَلْيُنفِقْ مِمَّآ ءَاتَىٰهُ ٱللَّهُ لَا يُكَلِّفُ ٱللَّهُ نَفْسًا إِلَّا مَآ ءَاتَىٰهَا سَيَجْعَلُ ٱللَّهُ بَعْدَ عُسْرٍ يُسْرًا

   Let him who has abundance spend out of his abundance and whoever has his means of subsistence straitened to him, let him spend out of that which Allah has given him; Allah does not lay on any soul a burden except to the extent to which He has granted it; Allah brings about ease after difficulty.