In God "there is no variation or shadow due to change." 26 God is "HE WHO IS", from everlasting to everlasting, and as such remains ever faithful to himself and to his promises.
Catechism number 221
But St. John goes even further when he affirms that "God is love":44 God's very being is love. By sending his only Son and the Spirit of Love in the fullness of time, God has revealed his innermost secret:45 God himself is an eternal exchange of love, Father, Son and Holy Spirit, and he has destined us to share in that exchange.
IV. THE IMPLICATIONS OF FAITH IN ONE GOD