AsSalam Alikum, What is the meaning of "Labbaik Ya Rasool Allah"? Are People say this coz of greeting or for supplication? Confused!

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.

Ibn Battaal assigned two meanings to the word Labbayk in his commentary on Al-Bukhari's Saheeh; he said: "Ibn Al-Anbaari said that the meaning of Labbayk is, 'I insist on being obedient to you'; and the meaning of Sa‘dayk is derived from 'to make someone happy' and to follow up on someone. Others said: the meaning of Labbayk is 'to obey you again and again', and the meaning of Sa‘dayk is 'to make you happy again and again.'" [End of quote]

Accordingly, if one says, "Labbayk ya Rasool Allaah (Labbayk O Messenger of Allaah) intending by that to say that he insists on being obedient of the Prophet, sallallaahu ‘alayhi wa sallam, to emphasize the will to follow his guidance, then this meaning is correct.

However, if someone believes that the Prophet, sallallaahu ‘alayhi wa sallam, is speaking to him and he is replying to the Prophet by saying Labbayk, or that he intends by it to invoke the Prophet, sallallaahu ‘alayhi wa sallam, then it is absolutely forbidden to say it; and it may be better not to say it, because ignorance is widespread among the people and they do not know the meaning of this word.

Shaykh Saalih Al-Fawzaan, may Allaah protect him, was asked: "There are stickers in shops, on which it is written: 'Labbayk, O Messenger of Allaah!' Is it permissible to say this phrase? Is it Shirk? What is our duty with respect to it?"

He replied: "Labbayk is only for Allaah, The Almighty: Labbayk Allaahumma Labbayk; Labbayk laa Shareeka laka Labbayk.

As regards saying: 'Labbayk, O Messenger of Allaah!', if the Messenger, sallallaahu ‘alayhi wa sallam, calls you and says: O so and so, and you respond: 'Labbayk, O Messenger of Allaah!' as the Companions used to say when he called them, then this is acceptable. But after his death, do not say: 'Labbayk, O Messenger of Allaah'; you should only say: 'Labbayk Allaahumma Labbayk." [End quote]

For more benefit, please refer to Fataawa 82007 and 83787.