Hadhrat Abu Hoerairah رضي الله عنه reports that Rasoeloul-laah ﷺ said: “When a pilgrim proceeds on his Hajj journey with money, provisions and his means of conveyance all acquired by lawful and halaal carnings, then when he embarks on his means of transport, and cries: Labbaik, O Al-laah; Labbaik. A caller from the heavens, an Angel, calls out to him: Welcome indeed to you, and may you be happy, your provisions are proper (halaal), your means of transport is proper, paid for from halaal earnings, and your Hajj shall be righteous and accepted by Al-laah.’ And when he proceeds for Hajj with unlawful and haraam earnings, placing his foot in the stirrup, and cries, Labbaik, O Al-laah a caller from the heavens, an Angel, calls out to him: No welcome to you, and no happiness, your provisions are unlawful (haraam) and so also are your earnings and your Hajj is rejected”.
“The Hadieth speaks for itself Another Hadieth says: “When a person goes to perform Hajj with improper (haraam) earnings, and says: ‘Labbaik’, Al-laah replies to him: You are not welcome, you have been rejected.” In another Hadieth, Al-laah replies: ‘Your Hajj is rejected”.”And in one Hadieth it says: “His Hajj is folded up and is thrown back in his face.
“Further in another Hadieth it is said: “When a person with haraam earnings goes for Hajj, his journey is not considered to be in Al-laah’s obedience. When he thus cries out ‘Labbaik’, while sitting on his means of conveyance, the Angels answer him saying: ‘No welcome for you, and no glad tidings. Your earnings are haraam, and also your clothing, your conveyance and your provisions. Turn back wicked and condemned”And when a person with halaal earnings cries out: Labbaik’, while seated on his means of transport, the Angels also cry out: ‘Labbaik’ together with saying: Your earnings are halaal, and so too is your clothing, your passage and your provisions. Return from here with a righteous and accepted Hajj and you have no corruption and no evil’.”It is reported in a Hadieth that Moosa Alaihis Salaam came for Hajj and when he cried out “Labbaik” during his walk from ‘Safaa to Marwah, he heard a voice from above saying:لبيك عبدي أنا معك . (در منثور )”Labbaik, O my servant, I am with you.” When Moosa Alaihis Salaam heard this, he fell down prostrating himself before Al-laah.(Doerre Manthoor)
Refer to the incident of Hadhrat Zainoel Aabiedien’s Rahmatullahi Alaih as recorded, when he said “Labbaik” his face became pale and his whole body began to shiver. Then someone asked him, “Why is this happening to you?” he replied, “For fear of being replied, La Labbaik,” (no welcome nor any glad tidings for you-your ‘Labbaik’ is not accepted.)
Moulana Zakariyya Khandhlawi Rahmatullahi Alaihi- Fadhaail-E-Hajj