There’s no two ways about it…. Syncretism, (broad) ecumenism, (alternative religious) “inclusiveness,” and (acceptive) tolerance are all antithetical to true religion. We should strive to live peaceably with all who reject the True Gospel but we should never validate, support, or defend them in their error.
Put on the whole armour of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
Spiritual Wrestlings 