Catechism of the Catholic Church §2023 — excerpt
Sanctifying grace is the gratuitous gift of his life that God makes to us; it is infused by the Holy Spirit into the soul to heal it of sin and to sanctify it.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.