Catechism of the Catholic Church

The apostolic faith concerning the Spirit was confessed by the second ecumenical council at Constantinople (381): "We believe in the Holy Spirit, the Lord and giver of life, who proceeds from the Father." By this confession, the Church recognizes the Father as "the source and origin of the whole divinity." But the eternal origin of the Spirit is not unconnected with the Son's origin: "The Holy Spirit, the third person of the Trinity, is God, one and equal with the Father and the Son, of the same substance and also of the same nature.... Yet he is not called the Spirit of the Father alone,... but the Spirit of both the Father and the Son." The Creed of the Church from the Council of Constantinople confesses: "With the Father and the Son, he is worshipped and glorified." (152, 685)