• إِصْر
• إِصْرهُمْ
• إِصْرى

Appears 3 times in the Quran.

1. 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.
   

2. 3:81 وَإِذْ أَخَذَ ٱللَّهُ مِيثَٰقَ ٱلنَّبِيِّۦنَ لَمَآ ءَاتَيْتُكُم مِّن كِتَٰبٍ وَحِكْمَةٍ ثُمَّ جَآءَكُمْ رَسُولٌ مُّصَدِّقٌ لِّمَا مَعَكُمْ لَتُؤْمِنُنَّ بِهِۦ وَلَتَنصُرُنَّهُۥ قَالَ ءَأَقْرَرْتُمْ وَأَخَذْتُمْ عَلَىٰ ذَٰلِكُمْ إِصْرِى قَالُوٓا۟ أَقْرَرْنَا قَالَ فَٱشْهَدُوا۟ وَأَنَا۠ مَعَكُم مِّنَ ٱلشَّٰهِدِينَ

   And when Allah made a covenant through the prophets: Certainly what I have given you of Book and wisdom-- then an messenger comes to you verifying that which is with you, you must believe in him, and you must aid him. He said: Do you affirm and accept My compact in this (matter)? They said: We do affirm. He said: Then bear witness, and I (too) am of the bearers of witness with you.
   

3. 7:157 ٱلَّذِينَ يَتَّبِعُونَ ٱلرَّسُولَ ٱلنَّبِىَّ ٱلْأُمِّىَّ ٱلَّذِى يَجِدُونَهُۥ مَكْتُوبًا عِندَهُمْ فِى ٱلتَّوْرَىٰةِ وَٱلْإِنجِيلِ يَأْمُرُهُم بِٱلْمَعْرُوفِ وَيَنْهَىٰهُمْ عَنِ ٱلْمُنكَرِ وَيُحِلُّ لَهُمُ ٱلطَّيِّبَٰتِ وَيُحَرِّمُ عَلَيْهِمُ ٱلْخَبَٰٓئِثَ وَيَضَعُ عَنْهُمْ إِصْرَهُمْ وَٱلْأَغْلَٰلَ ٱلَّتِى كَانَتْ عَلَيْهِمْ فَٱلَّذِينَ ءَامَنُوا۟ بِهِۦ وَعَزَّرُوهُ وَنَصَرُوهُ وَٱتَّبَعُوا۟ ٱلنُّورَ ٱلَّذِىٓ أُنزِلَ مَعَهُۥٓ أُو۟لَٰٓئِكَ هُمُ ٱلْمُفْلِحُونَ

   Those who follow the Messenger-Prophet, the Ummi, whom they find written down with them in the Taurat and the Injeel (who) enjoins them good and forbids them evil, and makes lawful to them the good things and makes unlawful to them impure things, and removes from them their burden and the shackles which were upon them; so (as for) those who believe in him and honor him and help him, and follow the light which has been sent down with him, these it is that are the successful.