God the Holy Spirit, the Third Person of the Blessed Trinity, is God just as the Father and the Son are God.

He is called the Paraclete (or Comforter) and the Advocate, because He pleads mankind’s cause with God. He is also called the Spirit of Truth, the Spirit of God, and the Spirit of Love. The Holy Spirit comes to us when we are baptized, and He continues to dwell within us and sanctify us as long as we do not shut Him out by mortal sin.