Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.

Tawassul as mentioned above is a contentious issue among scholars. It is important for us to guard against shirk in all forms.

Tawhid or worship of Allah alone is the quintessence of Islamic monotheism. Once we take this for granted the question arises are we allowed to pray to Allah by invoking the rights of Prophet Muhammad or other righteous people.

There is no doubt; we are allowed to pray to Allah by invoking the best of our deeds as we learn from the story of the three people stranded in the cave. Likewise, the Prophet taught us to pray invoking the rights of those entreat to Him.

In light of these, many eminent scholars of the past have considered it permissible to pray to Allah by invoking the good deeds or the excellence of the friends of Allah.

It is not the same as taking them as intermediaries in worship.

However, some scholars who condemn even this form of Tawassul as akin to shirk. It is an extreme view.

While saying this, it is important to point out that in the case of doubt we ought to stick to that which is well-established methods and practices of the pious elders.

There is not much evidence in the sources to suggest that the eminent companions used to pray to Allah by invoking the name of the Prophet (peace be upon him) or other righteous people.

There are those who question the veracity of the above reports attributed to Imam Shafi` or Imam Ahmad.

Dubious or unconfirmed reports cannot prove matters of worship and `aqidah.

Allah Almighty knows best.