Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions.
As to what follows:
There is unanimous consensus among Muslims that calling on other than Allah Almighty and asking them for that which none is capable of giving except Allah, amounts to kufr (disbelief) in Allah Almighty. Allah said:
“And that the masjids are for Allah, so do not invoke anyone with Allah.” [Al-Jinn 72:18]
And He said:
“And do not invoke besides Allah that which neither benefits you nor harms you, for if you did, then indeed you would be of the wrongdoers.” [Yunus 10:106]
And He said:
“And who is more astray than he who invokes besides Allah those who will not respond to him until the Day of Resurrection, and who are [even] unaware of their invocation.” [Al-Ahqaf 46:5]
There is no doubt that whoever calls on the Messenger of Allah (peace be upon him) or any other created being, has taken other than Allah as equals to Him calling upon them. Allah has condemned these people and ruled on their kufr. He Almighty said:
“To Him alone is the supplication of truth. And those they call upon besides Him do not respond to them with a thing, except as one who stretches his hands toward water [from afar, calling it] to reach his mouth, but it will not reach it thus. And the supplication of the disbelievers is not but in error [i.e. futility].” [Al-Ra`d 13:14]
He has also described calling upon other than Him as being falsehood. He said:
“That is because Allah is the Truth, and that which they call upon other than Him is falsehood, and because Allah is the Most High, the Grand.” [Al-Hajj 22:62]
This includes calling upon other than Allah whether it be calling upon the Messenger or calling upon anyone else.
He who says, “Help, O Messenger of Allah,” or, “Help, O Badawi,” is asking a created being for increase in strength; while help in the absolute sense is not to be asked for except from Allah Almighty, as He said:
“It is You we worship and You we ask for help.” [Al-Fatihah 1:5]
As for a created being, he is to be asked for what he is capable of giving, if he is present. As for the dead or non-present, then it is impermissible to seek help from them.
As for your question concerning the Salaf, and whether any of them did that, then that is not known concerning any of them. Shaykh al-Islam Ibn Taymiyyah (may Allah be pleased with him) said, “It has not been reported that any among the Salaf and Imams of knowledge called upon the dead or non-present, not the prophets nor other than them. Rather, it has only been mentioned by some contemporaries who are not from among the Mujtahid Imams of knowledge.” [Majmu` al-Fatawa (1/347)]
And Allah knows best.
Khalid bin `Abdullah al-Muslih
16 / 2 / 1425 AH