Tafseer of the aayah “And you might have seen the sun, when it rose, declining…”
Question

                Please explain the following verse.

“And you might have seen the sun, when it rose, declining to the right from their Cave, and when it set, turning away from them to the left, while they lay in the midst of the Cave. That is (one) of the Ayaat (proofs, evidences, signs) of Allaah. He whom Allaah guides, he is the rightly-guided; but he whom He sends astray, for him you will find no Wali (guiding friend) to lead him (to the Right Path)”
[al-Kahf 18:17 –interpretation of the meaning]
Praise be to Allah. 
          Shaykh Ibn Sa’di (may Allaah have mercy on him) said: 
 
          Allaah protected them from the sun, so He guided them 
          to go into a cave, and when the sun rose it declined to the right and 
          when it set it declined to the left, so that its heat would not reach 
          them and cause their bodies to decay. 
 
          “while they lay in the midst of the Cave” 
 
          i.e., in the middle of the cave which was a spacious 
          area. That was so that they might have some air and breezes, and so 
          that they would not decay or disintegrate in a narrow space, especially 
          since they remained there for so long. This was one of the Signs of 
          Allaah which points to His power and His mercy towards them, and it 
          was a response to their prayers, and guided them and took care of them. 
          Hence Allaah says (interpretation of the meaning): 
 
          “He whom Allaah guides, he is the rightly-guided”, 
          i.e., there is no way to attain true guidance except from Allaah, for 
          He is the true Guide who shows the way to that which is best in this 
          world and in the Hereafter. 
 
          “but he whom He sends astray, for him you will find 
          no Wali (guiding friend) to lead him”
i.e., you will not 
          find anyone to help him or guide him towards that which is good for 
          him, because Allaah has decreed that he is to be misguided and there 
          is none who can overturn His ruling. 
 
          See Tayseer al-Kareem al-Rahmaan, p. 472.