I want to ask about Tawassul (invoking Allaah, by means of an intermediary), is it permissible in Islam?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

There are two categories of Tawassul. One is permissible and the other is prohibited. 

The permissible category has three types:

1-   Tawassul by means of the Names and Attributes of Allaah;  Allaah Says (what means):

·        {And to Allah belong the best names, so invoke Him by them. And leave [the company of] those who practice deviation concerning His names. They will be recompensed for what they have been doing.} [Quran 7:180]

·        {O you who have believed, fear Allaah and seek the means [of nearness] to Him and strive in His cause that you may succeed.} [Quran 5:35]

2-   Tawassul to Allaah by virtue of a person’s   righteous deeds. Ibn 'Umar, narrated on authority of the Prophet the story of the three persons who were blocked inside a cave by a huge stone and each of them supplicated Allaah to get them out of the cave by virtue of a good deed he had done.  [Al-Bukhari and Muslim]

3-   Tawassul by a righteous living man supplicating for others.  It was narrated on the authority of ‘Uthmaan Ibn Abi Al-‘Aas that a blind man made Tawassul to Allaah The Almighty by means of the Prophet, sallallaahu ‘alayhi wa sallam, saying, "I invoke  You by means of Your Prophet, sallallaahu ‘alayhi wa sallam… so make him intercede for me with You". [Abu Daawood and Ibn Maajah]

This man's saying "make him intercede for me with You" proves that the meaning of seeking the Tawassul of the Prophet, sallallaahu ‘alayhi wa sallam, is seeking Tawassul by his, sallallaahu ‘alayhi wa sallam, supplication and not with the person of the Prophet, sallallaahu ‘alayhi wa sallam.  This is also supported by what ‘Umar Ibn Al-Khattaab did when they  suffered  draught: he sought the Tawassul of Al-‘Abbaas, the uncle of the Prophet, sallallaahu ‘alayhi wa sallam, to supplicate Allaah and it rained with the permission of Allaah. [Al-Bukhari] Had pleading to Allaah by means of the person of the Prophet, sallallaahu ‘alayhi wa sallam, been permissible, then they would have made Tawassul by means of the person of the Prophet, sallallaahu ‘alayhi wa sallam, after his death as well, as his status and honor during his life remained the same after his death.

The prohibited category contains two types:

1.   Tawassul that is considered a religious innovation, such as making Tawassul by means of the person of the prophets or righteous persons. The evidence for this is that Tawassul is an act of worship and all acts of worship are only done if they are proven by an authentic text , as indicated by the previous narration of ‘Umar .

2.   Tawassul which is considered an act of Shirk [associating partners with Allaah], such as making Tawassul by means of acts of worship (supplicating, vowing, sacrificing) for the sake of other than Allaah , then alleging that this is for the purpose of making them (to whom the act was done) intercede for them with Allaah. Allaah Says about polytheists (what means):

·        {We only worship them that they may bring us nearer to Allah in position} [Quran 39:3]

·        {And they worship other than Allah that which neither harms them nor benefits them, and they say, "These are our intercessors with Allah "} [Quran 10:18]

Allaah Knows best.