All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There are two matters here:
A) The issue of Tawassul, i.e. asking intercession by virtue of the Prophet and by his person after his death. This issue is a matter of difference of opinion among the scholars. Believing in its permissibility or uttering such an expression as a way of seeking intercession to Allah is not Shirk. Rather, it is an issue of difference of opinion as we have already mentioned.
For example, Shaykh Ibn Taymiyyah prohibited intercession by the virtue and person of the Prophet as elaborated in his book entitled: Qaa’idah Jaleelah fit-Tawassul wal-Waseelah, and he understood that the story of the blind person means that it is permissible to seek intercession by means of his supplication only.
Shaykh ‘Ezz-ad-Deen Ibn Abdus-Salaam, permitted seeking intercession by the person of the Prophet especially [but not with other people], with evidence of this Hadeeth. Besides, some scholars permitted seeking intercession by virtue of all the righteous people as inference to what was reported in this Hadeeth.
The view that we adopt here in Islamweb and which we consider to be the preponderant opinion is the view of Shaykh Ibn Taymiyyah and those who agreed with him, that it is prohibited to seek intercession by the person of the Prophet or by his virtue as a way of avoiding what is prohibited and because this was not reported from the righteous predecessors.
However, the issue is a matter of difference of opinion that does not involve any innovation or misguidance.
B) The second matter is addressing the Prophet directly and asking him to supplicate Allah to intercede for the person after his death: This is not permissible at all, and it is minor Shirk.
Shaykh Ibn Taymiyyah said:
“Allah forbade us from supplicating the angels and the Prophets even though he informed us that the angels supplicate for us and seek forgiveness for us. Despite this fact, we are not allowed to ask that [i.e. seek intercession] from them. Also, we are not allowed to seek intercession from the Prophets and the righteous people although they are alive in their graves, and even if we presume that they supplicate for the living people. Even if some Islamic texts were reported in this regard, no one is permitted to ask that from them. No one among the Salaf (righteous predecessors) did that because it is a reason that leads to committing Shirk of them and worshiping them instead of worshiping Allah, contrarily to asking one of them while he was alive which does not lead to Shirk.” [End of quote]
Allah knows best.