Augustine of Hippo on Sabellianism

[Reformed Covenanter]

... It is I and the Father who sent me is what you hear; “it is I and the one who sent me.” Do not jettison a person, distinguish persons. Distinguish intelligently; do not separate them perfidiously, lest, after steering clear of Charybdis, you crash on Scylla. The whirlpool of Sabellian impiety, you see, was about to suck you into saying the Father is the same as the Son; just now you have learned that I am not alone, but it is I and the Father who sent me. You acknowledge that the Father is Father and the Son is Son. You do well to acknowledge this; but do not go on to say, “The Father is greater, the Son is less.” Do not say, “The Father is gold, the Son is silver.” There is one substance, one godhead, one coeternity, perfect equality, not the least unlikeness. I mean, if you only believe that Christ is another, and that he is not the Father, yet you still think that he differs in nature, you have indeed avoided Charybdis but have wrecked yourself on Scylla’s rocks.

Navigate down the middle, avoid each dangerous shore. The Father is Father, the Son is Son. You are now saying, “The Father is Father, the Son is Son”; you have truly avoided the danger of being sucked into the whirlpool. Why do you want to go to the other side, and say, “The Father is one thing, the Son another”? One person, another person, yes, that is right; one thing and another thing, that is wrong. The Son, after all, is another person, because he is not who the Father is; and the Father is another person, because he is not who the Son is; not, however, another thing, but both Father and Son are the very same. What does that mean, the very same? It is one God. ...

For more, see Augustine of Hippo on Sabellianism.