In the marriage contract of the noble existence of Amir al-Mu'minin (the Commander of the Faithful, Imam Ali) and Fatimah Zahra (peace be upon them), The Messenger of God, said: "إنّ اللهَ جَعَلَ الْمُصَاهِرَةَ نَسبَاً لاحِقَاً"; (Indeed, Allah has made kinship through marriage as a subsequent lineage), He said that this bond of the bride and groom results kinship, it makes them relatives, they become lineage, not just to be called as in-laws. The bride is like the daughter of the groom's family, the groom is like the son of the bride's family.
When the noble existence of the Messenger of God accepted the proposal of Amir al-Mu'minin (the Commander of the Faithful) and it was decided that he would read the marriage contract, [he said] -this statement is a very subtle statement-, he said: "زَوَّجْتُكَ إِبْنَتِی فَاطِمَة عَلَي مَا زَوَّجَكَ الرَّحْمن"; (I give my daughter Fatimah in marriage to you based on what the Merciful has given you in marriage), How the Divine Essence bound the marriage of these two persons, God knows, and the one who went on the ascension, God knows, and the one who has said it! How the noble existence of the Messenger of God (may blessings and praise be upon him and his family) heard from the Divine that He recited the sermon of Zahra and Ali (peace be upon them), then the noble existence of the Messenger of God said: "According to that, I have recited it!"
When the noble sermon was recited by the noble existence of the Esteemed Messenger, the noble existence of the Commander of the believers prostrated in thankfulness.