The great Prophet (s.a.w) of Islam said after a long lecture:
"O the people! You are so many that can not shake hands of allegiance with me one by one; but I am ordered to make you confess to the Imamate and leadership of Ali (a.s). Also, you have to confess to the Imamate of his infallible children."
We likewise swear allegiance to His Wilayat and follow them by repeating the same sentences:
O our Prophet! We acknowledged and consented to what you delivered to us and did by the order of God, appointing Hadrat Ali (a.s) and the Imams after him as your real successors. Now we pledge allegiance by heart, hands and tongues to you for accepting Wilayat and take an oath to live and die with this holy belief.
We promise that we would stay with it even if when we get alive in the resurrection day. We don't alter it and don't doubt about it. We obey Allah, his Prophet (s.a.w), Amirulmuminin (a.s), his children Hasan, Hussein and the other Imams (a.s) who will come from Ali's generation.
We promise that we wouldn't replace anyone with him. God is our witness to this fact and he is sufficient for it. Also we ask you to be our witness.