The most insidious movement away from the foundations of Christianity has to do with the failure to recognize Christ Jesus as the One and only God of the OldTestament. He is our Creator, Saviour, Healer, Deliverer, Lord, King and Judge. The doctrine of the trinity is surely a strange doctrine which Jesus never taught or intimated. It tries to make 3 into 1 and 1 into 3. We are to have ^no other gods before^ Him. The Him is Jesus.
The second most damning movement is the turning away from the Word as the authority for all Truth. The determination that the Word was written for an earlier age is such a strange and false doctrine.
The third most damning movement is the turning away from the HolySpirit as the inspiration and power of all things that are good. Jesus constantly referred to His HolySpiritFather with whom He is one, demanding that His disciples receive comfort, help and teaching from Him once they were filled with Him. Those who have parked the Gospel at the Cross fail to understand that the Cross was the necessary step toward us to being SpiritFilled Mat 3:11.