Rabee‘ah bin ‘Ibaad (radhiyallahu ‘anhu) says:
I once saw Rasulullah (sallallahu ‘alaihi wasallam) in the markets of ‘Ukkaaz and Zul Majaaz inviting people towards Islam saying:
يا أيها الناس قولوا لا إله إلا الله تفلحوا
O people! Say “Laa Ilaaha Illallah” and you will be successful!
While he was inviting people towards Islam, I saw a squint-eyed man walking behind him and calling out to the people, “This man has renounced the religion of his forefathers and he is a liar!” When I asked the people who this man was, they informed me that he was the uncle of Rasulullah (sallallahu ‘alaihi wasallam), Abu Lahab.
According to another version of this Hadith, Rasulullah (sallallahu ‘alaihi wasallam) was calling the people saying:
يا أيها الناس إن الله يأمركم أن تعبدوه ولا تشركوا به شيئا
O people! Allah commands you to worship Him and to abstain from ascribing any partner unto him!
While Rasulullah (sallallahu ‘alaihi wasallam) was inviting the people towards Islam, Abu Lahab walked behind him calling out:
يا أيها الناس إن هذا يأمركم أن تتركوا دين آبائكم
O people! This man is commanding you to renounce the religion of your forefathers! Do not listen to him!
The pinnacle of Allah’s creation, Rasulullah (sallallahu ‘alaihi wasallam), was inviting people towards Islam and Daar-us-Salaam (Jannah) while Abu Lahab was calling people towardsنارا ذات لهب(the blazing fire of Jahannum).
(Extracted from Seeratul Mustafaa 1/179)