What is the punishment of saying "yaa Mohammad", and "yaa 'Ali, Faatimah, Hassan, and Husseyn"?

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 is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The Qur'aan, narrations of the Prophet and consensus of the Muslim scholars prove that Tawheed (belief in oneness of Allaah) is an obligation on every Muslim.

Allaah says (interpretation of meaning): {And I did not create the jinn and mankind except to worship Me.}[51:56].

It is also the consensus of the Muslim scholars that whoever appoints mediators between himself and Allaah so that he calls them, trusts in them, seeks their help, etc., is committing disbelief. Allaah says (interpretation of meaning): {And who is more astray than he who invokes besides Allaah those who will not respond to him until the Day of Resurrection [i.e. never], and they, of their invocation, are unaware.}[46:5].

The Prophet said: "Supplicating Allaah is a form of worship," then he recited the verse: {And your Lord says, Call upon Me; I will respond to you.}[40:60].

If one by his sayings "Ya 'Ali" and "Ya Mohammad" intends to call them, and seek their help then it is disbelief as we mentioned above.

Supplicating Allaah has two meanings in Islaamic terminology:

First, supplicating Allaah to mean worshipping: the evidence is this verse: {So do not worship with Allaah another deity and [thus] be among the punished}[26:213].

Second, supplicating Allaah to mean asking Him for one's needs, whether to accomplish beneficial things or prevent harmful things from befalling him, etc: the evidence is the saying of Allaah (interpretation of meaning): {Say, “Have you considered: if there came to you the punishment of Allaah or there came to you the Hour — is it other than Allaah you would invoke, if you should be truthful?}[6:40].

Seeking help means asking the support and help of some creatures in a matter of which Allaah alone has the power and control to grant such as granting provision, forgiving sins, etc.

So, whoever believes that the Prophet or 'Ali or Faatimah are able to help him, is committing disbelief. Ibn Taymiyyah said: 'Whoever ascribes to someone the attributes and qualities that only belong to Allaah is a disbeliever provided that the proofs that show his disbelief have been clarified to him. This is the consensus of all Muslim scholars.'

Ibn Taymiyyah also said: 'The Bid'ah (innovations) that leads to disbelief were innovated in the late centuries. It was not known in the period of pious predecessors to seek help from other than Allaah.'

Allaah knows best.