Who is the Holy Spirit?

The Holy Spirit is God and the third Person of the Blessed Trinity.

(a) The Holy Spirit is also called the Holy Ghost, the Paraclete, the Advocate, the Spirit of Truth, the Spirit of God, and the Spirit of Love.

From whom does the Holy Spirit proceed?

The Holy Spirit proceeds from the Father and the Son.

(a) The Holy Spirit does not proceed from the Father and the Son by spiritual generation. Only the Son proceeds from the Father by generation. This is one of the mysterious truths that we know only from revelation.

Is the Holy Spirit equal to the Father and the Son?

The Holy Spirit is equal to the Father and the Son, because He is God.

(a) Because of the oneness of nature in the Blessed Trinity, the Father is entirely in the Son and in the Holy Spirit; the Son is entirely in the Father and in the Holy Spirit; and the Holy Spirit is entirely in the Father and in the Son. No one of the three divine Persons is outside the other, for none precedes the other in eternity, nor surpasses the other in power, nor exceeds the other in any way. This indwelling of one divine Person in the others is called circumincession.

What does the Holy Spirit do for the salvation of mankind?

The Holy Spirit dwells in the Church as the source of its life and sanctifies souls through the gift of grace.

(a) Although the sanctification of mankind, like all other outward works of God, is performed by all three Persons of the Blessed Trinity, it is attributed to the Holy Spirit, the third Person. The sanctification of mankind is attributed to the Holy Spirit because He is the love of the Father and the Son and because the sanctification of man by grace shows forth God's boundless love.