Commentary
Several verses earlier, the text was dealing with the people of the Book, their false beliefs and their doubts. Then, appeared the mention of بیت اللہ Baytullah and Hajj. Now once again, the people of the Book are the addressees. These verses relate to a particular event. There was a Jew, Shammas ibn Qays, who harboured a chronic malice against Muslims. Once, when he saw two Ansar tribes, Aws and Khazraj, gathered together amiably at one place, his malevolence got the better of him and he went about looking for ways to sow seeds of discord between them. Finally, he set up a man suggesting to him that these two tribes have fought much long-drawn war in pre-Islam days and both parties had recited poetical compositions highlighting their tribal pride. So why not recite these self-congratulating poetical compositions while both sit together. The moment these poems were recited there, emotions rose high, there were charges and counter-charges to the limit that the place and time of a fresh war was all set. When the Holy Prophet ﷺ heard about this, he came to them and said: 'What is all this? Here I am present amidst you and you are doing this after having become Muslims and after having become united and friendly with each other. This is sheer ignorance. Do you want, in this state of yours, to revert to kufr?'
They took the warning to their hearts. They knew this was a slip caused by شیطان Satan. They embraced each other, wept and repented. These verses were revealed in the background of this event.
This event appears in Ruh al-Ma'ani as narrated by Ibn Ishaq while there are others who narrate it from Zaid ibn Aslam. This subject continues through several verses after this. Here, the verses begin with an admonition to the people of the Book who had engineered this in triage, and this admonition has been done with great eloquence when, before admonishing them for what they did, they were taken to task for their disbelief as well, which meant that it would have made better sense if they themselves had taken to the right path, and become Muslims, rather than devoting themselves to distract others to the wrong track. Following this, Muslims have been addressed, and served with a word of caution, especially when they have by their side, the Book and the Messenger of Allah, two powerful, never-failing sources, which would help them stay firm in their belief.
The expression وَمَن يَعْتَصِم بِاللَّـهِ ,'translated as 'And whoever holds on to Allah' means one who stays firm in, and totally committed to, his ایمان 'iman or faith, for اعتصام 'i` tisam', the act of holding on to Allah firmly, denotes that one should affirm His Being and His Attributes, be staunchly faithful to what He has ordained, and in the process, be sure not to be lured into supporting the position of any adversary whoever that may be. One who acts in this manner 'is surely guided to the straight path'. It means that such a person is on the 'straight path', and being on the 'straight path' is the key to all that is good and beneficial which the Word of Allah promises to him.