وَإِذِ ٱعْتَزَلْتُمُوهُمْ وَمَا يَعْبُدُونَ إِلَّا ٱللَّهَ فَأْوُٓا إِلَى ٱلْكَهْفِ يَنشُرْ لَكُمْ رَبُّكُم مِّن رَّحْمَتِهِ وَيُهَيِّئْ لَكُم مِّنْ أَمْرِكُم مِّرْفَقًا

When a man, on account of his devotion to truth, becomes isolated from his fellow-beings, he comes closer to God. He comes so close to his Lord that he can converse with God. He talks with his Lord and receives a response from Him. The new faith of the ‘Men of the Cave,’ their fearless preaching, their willingness to forego everything rather than to forego the right path, had all bestowed upon them the high status of nearness to God. Whatever they had apparently lost was nothing compared to what they had gained. It was this sense of achievement which enabled them to tolerate the loss of all else but the truth. They reconciled themselves to the position that they were living in a cave, renouncing the comforts of their homes and their town, while still entertaining the hope that God would help them and ameliorate their condition. Ibn Jarir has quoted ‘Ata as saying that they were seven in number. While in the cave, they used to pray to God, used to cry and seek His help. (Tafsir ibn Kathir). Finally God made them fall into a long deep slumber.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (18:16)