In verse 20, there is a refutation of the saying of those who had said that they had checked with the Jews and the Christians and none of them were ready to attest to his truth as a Messenger of Allah. About that it was said: الَّذِينَ آتَيْنَاهُمُ الْكِتَابَ يَعْرِ‌فُونَهُ كَمَا يَعْرِ‌فُونَ أَبْنَاءَهُمُ ; (That is, as for the Jews and Christians, they recognize Muhammad al-Mustafa as they would recognize their sons.

The reason is that there is, in the Torah and Injil, a full description of the physical features of the Holy Prophet ﷺ ، of his home city and then his post-emigration place of residence, and of his habits and morals and achievements - all this in such details that it leaves no room for doubt in the recognition of his identity. In fact, this is not limited to the mention of the Holy Prophet ﷺ the Torah and the Injil carry even the detailed description of his noble Sahabah as well. Therefore, there was no possibility that anyone who recited the Torah and the Injil and believed in them would be unable to recognize the Holy Prophet ﷺ .

At this point, the simile given in the text is that of children - ` as they would recognize their sons.' Not said here is: as children recognize their parents. The reason is that the recognition of children by parents is most detailed and certain. Children remain before parents day and night under all conditions. From infancy to younger years, they are raised in the hands and laps of parents. So, the extent to which parents can recognize their children, their children cannot recognize them.

Sayyidna ` Abdullah ibn Salam ؓ عنہ belonged to the Jewish faith, then he became a Muslim. Sayyidna Faruq al-A'zam ؓ asked him: Allah Ta` ala says in the Qur'an that you recognize our Rasul as you would recognize your sons. What is the reason for it? Sayyidna ` Abdullah ibn Salam said: Yes, we know the Holy Prophet ﷺ from his qualities and features revealed by Allah Almighty through the Torah. Therefore, this knowledge of ours is certain and absolute. This is contrary to our offspring about whom one could doubt whether or not they were their children.

Sayyidna Zayd ibn Sa'nah who first belonged to the people of the Book had recognized the Holy Prophet ﷺ through the description of his qualities and features stated in the Torah and the Injil. There was only one quality which could not be confirmed from earlier information. So, this he confirmed by testing. That quality was : ` His forbearance will dominate his anger.' Then, he went to see the Holy Prophet ﷺ ، made his test and found him a true bearer of this quality. He instantly became a Muslim.

In the last verse (21), it was said that these people of the Book who, despite knowing the true identity of the Holy Prophet ﷺ do not accept Islam were simply ruining themselves at their own hands: الَّذِينَ خَسِرُ‌وا أَنفُسَهُمْ فَهُمْ لَا يُؤْمِنُونَ (Those, who have brought loss on themselves, they are not going to believe).