Man in his life is constantly under the pressure of love for this world, love for possessions, love for positions and love for wife, children and other desires; these factors may make him go astray. He would never have reached man's perfection if God had not prepared for him some mechanisms to protect him. God has said:
"وَاعْتَصِمُوا بِحَبْلِ اللَّهِ جَمِيعًا وَلَا تَفَرَّقُوا"
“And hold fast by the covenant of Allah altogether and be not disunited”1
The question which is raised here is: What is meant by "The covenant of Allah"? Is it Islam, or Qur’an, or the Prophet's kinfolks?
The fact is that by "the covenant of Allah" is meant any means which leads him to the Divine aims. On the other hand, "The covenant of Shaitan" leads him astray.2
Thus, the Qur’an, Islam and the Prophet's family could be used as covenants, as it is written in traditions.3
The tradition of Abi Sa'eed al-Khudri narrated from the Prophet confirms this fact: The Prophet said,
"ايُّها النّاسُ اِنِّي قَد تَرَكْتُ فِيكُم حَبلَينِ، اِن اتَّخَذتُم بِهِمَا لَن تَضِلُّوا بَعدِي، اَحَدُهُمَا اَكبَر مِنَ الآخَرِ: كِتابَ الله حَبلٌ مَمدُودٌ مِنَ السَّماءِ اِلى الارْضِ وَعِترَتِي اَهلَ بَيتِي اِنَّهُما لَن يَفتَرِقا حَتّى يَرِدَا عَليَّ الحَوضَ"
"O people! I have left among you two cords (covenants). If you grasp them both, you will not go astray after me. One is greater than the other: the Book of God (the Qur’an), is a cord that extends from the heavens to the earth; and my near relations, the people of my house. The two will never part until they join me at the (Kawthar) pool."4
As you will notice, the Prophet of Islam negates separation on condition that we grasp those two cords. Or else, it will be useless because a sick man will not cure himself if he has the prescription and the drug without acting upon them. Islam, Qur’an and Prophet's family can not cure our spiritual and mental disturbances unless we obey God's command as issued in the Qur’an and stated by the Prophet's family members.
It is for this reason that Imam ‘Ali recommends that his son – and all his spiritual sons as well – connect themselves with God's rope. He has emphasized that there is no bond and covenant stronger than that between God and mankind. This is on condition that one should act as he is ordered.