It is narrated from Sayyiduna Mu'adh (may Allah be pleased with him) that I was riding behind the Prophet (peace and blessings of Allah be upon him) when he said: "O Mu'adh," I replied, "At your service and at your pleasure." Then the Prophet (peace be upon him) said this three times, (then said:) "Do you know what Allah's right is upon His servants? It is that they worship Him and do not associate anything with Him." Then after traveling a little further, he said: "O Mu'adh?" I replied, "At your service and at your pleasure." The Prophet (peace be upon him) said: "Do you know what the servants' right is upon Allah, Mighty and Majestic, when they do this? It is that He does not punish them."
Hadith Referenceالادب المفرد / كتاب العطاس والتثاؤب / 943
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : صحيح البخاري ، الرقاق ، ح : 6500 و مسلم ،كتاب الإيمان : 48»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: The meaning of "Labbayk" is "I am present," and the meaning of "Sa'dayk" is "I am here to comply with your command and consider it my good fortune." "Labbayk" is the word of talbiyah; therefore, the question could arise whether it is permissible for servants (of Allah) to use this word or not. Imam Bukhari rahimahullah has established its permissibility.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 943