فَتَوَلَّوْاْ عَنْهُ مُدْبِرِينَ

(So they turned away from him and departed.) Qatadah said, "The Arabs say of one who thinks deeply that he is looking at the stars." What Qatadah meant is that he looked at the heavens thinking of a way to distract his people. So he said,

إِنِّى سَقِيمٌ

In verses 88 and 89, it was said: نَظَرَ‌ نَظْرَ‌ةً فِي النُّجُومِ فَقَالَ إِنِّي سَقِيمٌ. (Then, he cast a look at the stars, and then said, "I feel indisposed" 37:88-89). There is a background to these verses. The people of Sayyidna Ibrahim (علیہ السلام) used to have a festival on a particular day. When that day came, they invited Sayyidna Ibrahim to go with them and enjoy the festival. Their purpose was that if he accompanies them in the festival, he might be impressed with them and forget about calling them to his faith. (ad-Durr-ul-Manthur, Ibn Jarir and others). But, Sayyidna Ibrahim had something else on his mind. He wanted to make use of this occasion to pursue an agenda of his own. He thought when all these people go to celebrate their festival, he would have the time to go into their temple and break their idols, so that when they returned, they would see the helplessness of their false gods with their own eyes. It was quite possible that this scenario makes someone's heart lit with the spark of true faith and, may be, he repents and shies away from shirk. This being his aim, Sayyidna Ibrahim (علیہ السلام) refused to go with them. But, he chose a particular method of saying 'no' to his people when he cast a full, animated look at the stars (expressed in the text by saying: فِي النُّجُومِ fi-nnujum: into the stars ] as explained below) and then said that he was indisposed. His people took his excuse to be valid, left him alone and went away to enjoy their festival.

Several exegetic and juristic issues are related with this event. A gist is being presented here.