The Table Spread
۞ يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ لَا تَتَّخِذُوا۟ ٱلْيَهُودَ وَٱلنَّصَـٰرَىٰٓ أَوْلِيَآءَ ۘ بَعْضُهُمْ أَوْلِيَآءُ بَعْضٍ ۚ وَمَن يَتَوَلَّهُم مِّنكُمْ فَإِنَّهُۥ مِنْهُمْ ۗ إِنَّ ٱللَّهَ لَا يَهْدِى ٱلْقَوْمَ ٱلظَّـٰلِمِينَ
O you who have believed, do not take the Jews and the Christians as allies. They are [in fact] allies of one another. And whoever is an ally to them among you - then indeed, he is [one] of them. Indeed, Allah guides not the wrongdoing people.
Nearby ayahs help place verse 5:51 in sequence and meaning.
وَأَنِ ٱحْكُم بَيْنَهُم بِمَآ أَنزَلَ ٱللَّهُ وَلَا تَتَّبِعْ أَهْوَآءَهُمْ وَٱحْذَرْهُمْ أَن يَفْتِنُوكَ عَنۢ بَعْضِ مَآ أَنزَلَ ٱللَّهُ إِلَيْكَ ۖ فَإِن تَوَلَّوْا۟ فَٱعْلَمْ أَنَّمَا يُرِيدُ ٱللَّهُ أَن يُصِيبَهُم بِبَعْضِ ذُنُوبِهِمْ ۗ وَإِنَّ كَثِيرًا مِّنَ ٱلنَّاسِ لَفَـٰسِقُونَ
And judge, [O Muhammad], between them by what Allah has revealed and do not follow their inclinations and beware of them, lest they tempt you away from some of what Allah has revealed to you. And if they turn away - then know that Allah only intends to afflict them with some of their [own] sins. And indeed, many among the people are defiantly disobedient.
أَفَحُكْمَ ٱلْجَـٰهِلِيَّةِ يَبْغُونَ ۚ وَمَنْ أَحْسَنُ مِنَ ٱللَّهِ حُكْمًا لِّقَوْمٍ يُوقِنُونَ
Then is it the judgement of [the time of] ignorance they desire? But who is better than Allah in judgement for a people who are certain [in faith].
فَتَرَى ٱلَّذِينَ فِى قُلُوبِهِم مَّرَضٌ يُسَـٰرِعُونَ فِيهِمْ يَقُولُونَ نَخْشَىٰٓ أَن تُصِيبَنَا دَآئِرَةٌ ۚ فَعَسَى ٱللَّهُ أَن يَأْتِىَ بِٱلْفَتْحِ أَوْ أَمْرٍ مِّنْ عِندِهِۦ فَيُصْبِحُوا۟ عَلَىٰ مَآ أَسَرُّوا۟ فِىٓ أَنفُسِهِمْ نَـٰدِمِينَ
So you see those in whose hearts is disease hastening into [association with] them, saying, "We are afraid a misfortune may strike us." But perhaps Allah will bring conquest or a decision from Him, and they will become, over what they have been concealing within themselves, regretful.
وَيَقُولُ ٱلَّذِينَ ءَامَنُوٓا۟ أَهَـٰٓؤُلَآءِ ٱلَّذِينَ أَقْسَمُوا۟ بِٱللَّهِ جَهْدَ أَيْمَـٰنِهِمْ ۙ إِنَّهُمْ لَمَعَكُمْ ۚ حَبِطَتْ أَعْمَـٰلُهُمْ فَأَصْبَحُوا۟ خَـٰسِرِينَ
And those who believe will say, "Are these the ones who swore by Allah their strongest oaths that indeed they were with you?" Their deeds have become worthless, and they have become losers.