Why do Jewish people call Christianity a religion of three gods?
Because from an Old Testament background, the Trinity is not clarified as it is in the New Testament. Jewish people therefore perceive the Christian teaching of Father, Son, and Holy Spirit—three co-equal persons in one Godhead—as polytheism, and describe it as a religion of three gods.
Les explains that the Godhead consists of God the Father, God the Son, and the Holy Spirit, and that all three are co-equal members of the Godhead. He notes that Paul puts Christ first in Colossians, but this does not change the Trinity's modus operandi. From their Old Testament background, Jewish people refer to Christianity as polytheism and call it a religion of three gods. The correction is that Christianity is not three gods but three persons in one God. The Old Testament does not clarify this as the New Testament does. Paul warns in Colossians 2:8–9 against philosophy and vain deceit, affirming that in Christ dwells all the fulness of the Godhead bodily.