Keep always in mind the rule of faith which I profess and by which I bear witness that the Father and the Son and the Spirit are inseparable from each other, and then you will understand what is meant by it. Observe now that I say the Father is other [distinct], the Son is other, and the Spirit is other. This statement is wrongly understood by every uneducated or perversely disposed individual, as if it meant diversity and implied by that diversity a separation of Father, Son, and Holy Spirit
TertullianFor what war should we not be fit and eager, even though unequal in numbers, we who are so willing to be slaughtered-if, according to that discipline of ours, it was not more lawful to be slain than to slay?
Tertullian