WHOEVER talks only about the Spirit, comprehends in this confession also the One whose Spirit he is.
And since he is “the Spirit of Christ”, and since he is “from the Father”, as Paul says, so as in the case of a chain, when someone pulls on one end of it he pulls the other end along with it, so also the man who “draws the Spirit”, as the Prophet puts it, through him draws the Son and the Father along too.
And if anyone truly lays hold on the Son, he shall have hold of him from both sides: that is, in some sense taking him along with his Father, and the selfsame Spirit.
The one who exists in the Father cannot be cut off from him. Nor can he ever be parted from his own Spirit, who “works all things in him”.
Likewise, whoever has received the Father receives effectively along with him both the Son and the Spirit. There is no way in which we could conceive a cutting off or a separation, as if the Son could be imagined without the Father, or the Spirit parted from the Son.
St Basil the Great, Letter XXXVIII §4 (To his brother Gregory). There is another translation at CCEL.
COME ye peoples, let us worship the three-personed Godhead, the Son in the Father, with the Holy Spirit.
For the Father begat beyond time a Son who together with him is everlasting, and sitteth together with him upon one throne; and the Spirit was in the Father, glorified together with the Son: one power, one substance, one Godhead, which we all worship saying,
Holy God, which hath made all things through the Son, by the fellow-working of the Holy Spirit.
Holy and Mighty, through whom we have come to know the Father, and the Holy Spirit who has come to dwell in the world.
Holy and Immortal, the Spirit, the Comforter, which proceedeth from the Father, and resteth in the Son: Holy Trinity, glory be to thee.
Sunday of Pentecost, at Vespers just before “O Lord, now lettest thou thy servant depart in peace”.