Denying the Trinity: An Age-old Heresy

These days, many professing 'christians' deny the doctrine of the Trinity. Their argument is that if Father, Son and Holy Spirit are all God, we are worshipping three Gods (tritheism). By that same logic, if Jesus Christ is God, we have two Gods (bitheism). The doctrine of the Trinity is one God in three persons, individual and indivisible.
To deny the Trinity is to deny the deity of Christ, and to deny Christ's deity is to deny salvation.