Al Fatawa Al Hadeethiya Li Ibn Hajr Haitami, Matlabun Fi Jama'atin Yusalluna 'Alan Nabiyyi
Tarikh Dimashq Li Ibn Abi Asaker, Harful Alif
Mausu'a Fiqhiya Kuwaitiyyah, At Tawassul
Translation of Hadith: It has been narrated on the authority of Hadhrat Umar Bin Khattab (May Allah be well pleased with him), he said that the Holy Prophet (Sallallahu alaihi wa sallam) said: When Hadhrat Adam (Peace be upon him) committed an oversight, he supplicated to Allah Ta'ala: O my Lord! I pray with the Wasila of Hadhrat Muhammad (Sallallahu alaihi wa sallam), you forgive me. Allah Ta'ala said: O Adam! How do you know Hadhrat Muhammad (Sallallahu alaihi wa sallam). He has not yet arrived in the world. Hadhrat Adam (Peace be upon him) said: O my Lord! When you created me with your power and blew your Ruh (soul) into me, I raised my head and saw written on the supports of the 'Arsh:
"La Ilaha Illallah Muhammadur Rasulullah"
I understood that you had joined Your blessed name with His pure name who is the most beloved to you in the whole creation.
Allah Ta'ala said: O Adam! You have spoken the truth. Indeed! In the whole creation, He is the dearest to me. You supplicate to Me through His Wasila and I will surely grant you Maghfirah (forgiveness). If Hadhrat Muhammad (Sallallahu alaihi wa sallam) was not to be, I would not have created you.
There are many Traditions and incidents in this regard. The Dua taught by the Holy Prophet (Sallallahu alaihi wa sallam) to the blind Sahabi explains Tawassul (Wasila):
Translation of Dua: O Allah (Subhanahu Wa Ta'ala)! I supplicate to you and I turn to you with the Wasila of your Prophet of Mercy. O personification of praise (Sallallahu alaihi wa sallam), I have turned to my Lord with your Wasila, so that my need is fulfilled. O Allah