14 These things then, brethren, are declared by the Scriptures. And the blessed John, in the testimony of his Gospel, gives us an account of this economy (disposition) and acknowledges this Word as God, when he says, “In the beginning was the Word, and the Word was with God, and the Word was God.” If, then, the Word was with God, and was also God, what follows? Would one say that he speaks of two Gods? I shall not indeed speak of two Gods, but of one; of two Persons however, and of a third economy (disposition), viz., the grace of the Holy Ghost.
For the Father indeed is One, but there are two Persons, because there is also the Son; and then there is the third, the Holy Spirit. The Father decrees, the Word executes, and the Son is manifested, through whom the Father is believed on. The economy of harmony is led back to one God; for God is One. It is the Father who commands, and the Son who obeys, and the Holy Spirit who gives understanding: the Father who is above all, and the Son who is through all, and the Holy Spirit who is in all.
And we cannot otherwise think of one God, but by believing in truth in Father and Son and Holy Spirit. For the Jews glorified (or gloried in) the Father, but gave Him not thanks, for they did not recognise the Son. The disciples recognised the Son, but not in the Holy Ghost; wherefore they also denied Him. The Father's Word, therefore, knowing the economy (disposition) and the will of the Father, to wit, that the Father seeks to be worshipped in none other way than this, gave this charge to the disciples after He rose from the dead: “Go and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.” And by this He showed, that whosoever omitted any one of these, failed in glorifying God perfectly.
For it is through this Trinity that the Father is glorified. For the Father willed, the Son did, the Spirit manifested. The whole Scriptures, then, proclaim this truth.
Source: Against the Heresy of Noetus (New Advent)