The Iron
لِّئَلَّا يَعْلَمَ أَهْلُ ٱلْكِتَـٰبِ أَلَّا يَقْدِرُونَ عَلَىٰ شَىْءٍ مِّن فَضْلِ ٱللَّهِ ۙ وَأَنَّ ٱلْفَضْلَ بِيَدِ ٱللَّهِ يُؤْتِيهِ مَن يَشَآءُ ۚ وَٱللَّهُ ذُو ٱلْفَضْلِ ٱلْعَظِيمِ
[This is] so that the People of the Scripture may know that they are not able [to obtain] anything from the bounty of Allah and that [all] bounty is in the hand of Allah; He gives it to whom He wills. And Allah is the possessor of great bounty.
Nearby ayahs help place verse 57:29 in sequence and meaning.
ثُمَّ قَفَّيْنَا عَلَىٰٓ ءَاثَـٰرِهِم بِرُسُلِنَا وَقَفَّيْنَا بِعِيسَى ٱبْنِ مَرْيَمَ وَءَاتَيْنَـٰهُ ٱلْإِنجِيلَ وَجَعَلْنَا فِى قُلُوبِ ٱلَّذِينَ ٱتَّبَعُوهُ رَأْفَةً وَرَحْمَةً وَرَهْبَانِيَّةً ٱبْتَدَعُوهَا مَا كَتَبْنَـٰهَا عَلَيْهِمْ إِلَّا ٱبْتِغَآءَ رِضْوَٰنِ ٱللَّهِ فَمَا رَعَوْهَا حَقَّ رِعَايَتِهَا ۖ فَـَٔاتَيْنَا ٱلَّذِينَ ءَامَنُوا۟ مِنْهُمْ أَجْرَهُمْ ۖ وَكَثِيرٌ مِّنْهُمْ فَـٰسِقُونَ
Then We sent following their footsteps Our messengers and followed [them] with Jesus, the son of Mary, and gave him the Gospel. And We placed in the hearts of those who followed him compassion and mercy and monasticism, which they innovated; We did not prescribe it for them except [that they did so] seeking the approval of Allah. But they did not observe it with due observance. So We gave the ones who believed among them their reward, but many of them are defiantly disobedient.
يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ ٱتَّقُوا۟ ٱللَّهَ وَءَامِنُوا۟ بِرَسُولِهِۦ يُؤْتِكُمْ كِفْلَيْنِ مِن رَّحْمَتِهِۦ وَيَجْعَل لَّكُمْ نُورًا تَمْشُونَ بِهِۦ وَيَغْفِرْ لَكُمْ ۚ وَٱللَّهُ غَفُورٌ رَّحِيمٌ
O you who have believed, fear Allah and believe in His Messenger; He will [then] give you a double portion of His mercy and make for you a light by which you will walk and forgive you; and Allah is Forgiving and Merciful.