﴿ يَعْلَمُ مَا بَيْنَ أَيْدِيهِمْ وَمَا خَلْفَهُمْ وَلَا يَشْفَعُونَ إِلَّا لِمَنِ ٱرْتَضَىٰ وَهُم مِّنْ خَشْيَتِهِۦ مُشْفِقُونَ ﴾

“He knows all that lies open before them and all that is hidden from them: hence, they cannot intercede for any but those whom He has [already] graced with His goodly acceptance, since they themselves stand in reverent awe of Him.”

Please check ayah 21:29 for complete tafsir.