Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) once mentioned the following:
Ponder and think that the light of the religion of the Christians (and Jews) has been extinguished with the light of Islam which Nabi Muhammad (sallallahu ‘alaihi wasallam) brought (the Quraan and sunnah) – instead practising on their religion is no longer permissible as their religion has become abrogated by Allah Ta‘ala, and taking light from their religion has been declared prohibited by Allah Ta‘ala.
When it is not permissible for one to follow the Jews and Christians in their religion, which was actually revealed by Allah Ta‘ala, then for the Ummah of Rasulullah (sallallahu ‘alaihi wasallam) – who are the bearers of the Quraan and sunnah – to follow them in their lifestyle and ways, and to regard their lifestyle and ways to be the correct path – one can well imagine how reprehensible it will be and how much it will draw the wrath of Allah Ta‘ala upon them!
Even from a logical perspective, one will understand how wrong it is that while the Deen of Nabi Muhammad (sallallahu ‘alaihi wasallam) is preserved and safeguarded in its pristine form (in all branches of human life, whether individually or collectively, Deen has presented guidance for man, showing him the path to Allah Ta‘ala), then how can the way of the Christians (and Jews) be followed? Is this not showing gross ingratitude to the sharee‘ah and Deen which Nabi Muhammad (sallallahu ‘alaihi wasallam) has brought to us?
(Malfoozaat Hazrat Moulana Muhammad Ilyaas [rahmatullahi ‘alaih] pg. 82)
Source: Ihyaauddeen.co.za