Praise by the Enemy

Ma’mun (1) had decided to have his daughter, Umm al-Fadl, marry Imam Abu Ja’far Muhammad ibn Ali (A.S.). The other Abbasids who became aware of his decision reproached him and considered his decision obscene. They feared that this act would prepare the same grounds as it did previously with Imam Reza (A.S.). They gathered their thoughts and consulted as much as they could. Then a group of Ma’mun’s family gathered to talk to him about the issue. They told him: “…We fear that this act of yours may take away the dynasty, which Allah has granted us, and destroy our pride as a result. You are well aware of all the conflicts we have had with Ali’s progeny in the past. You are also aware that the previous Rashidin Caliphs would constantly banish and ignore Ali’s progeny as much as they could.….” 
Ma’mun replied: “But you yourself were the cause of all the conflicts between you and Abu Talib’s progeny. If you were fair with them, they were more deserving of the position than you.….”
The group then said: “…Are you going to allow your beloved daughter to marry a child who does not understand anything about the religion of Allah? A child who does not know what is allowed and what is not, and consequently does not know what is recommended and what is not? .. At Least give him some time to grow up and learn some manners. Let him learn to recite Quran and learn more about the religion of Allah …”
Ma’mun answered: “Woe onto you! I know this young man much better than you. His understanding of the religion of Allah exceeds your understanding. His knowledge towards Allah, the Prophet and his traditions are far more than yours. His recitation of the Quran is more fluent than yours; and his knowledge of the clear, unclear, reason of descent, inner, and outer verses of the Quran surpass your knowledge.” 
(Selection taken from:” Sireye Ma’sooman”, by Sayyid Musin Amin (with minor changes))
1- Ma’mun was one of the caliphs who ruled during the Abbasid Dynasty. He was the one who oppressively martyred Imam Reza (A.S.). This incident shows that he was aware of the Imams’ knowledge and insight in religion; however, he continued to oppress them and limit their activities just as his forefathers would. He was mysterious in controlling the Prophet’s progeny and he went so far until he married his daughter to Imam Jawad (A.S.) for political reasons.