The Latin word Fiat means “Let there be, or let it be, or let it be done.” Jesus often speaks to Luisa of the Supreme Fiat, which is synonymous with the Supreme (Divine) Will of God. Thus, when she writes of ‘the Fiat’ she refers to the Divine Will.
God begins His greatest works with His Supreme Fiat. The Fiat of Creation opens with God’s “Fiat lux” or “Let there be light” (Genesis 1:3), and everything in the world, including humanity, are willed into existence. The Fiat of Redemption begins with the Immaculate Conception of Blessed Virgin Mary, whose response of trusting obedience at the Annunciation “Fiat mihi secundum verbum tuum” or “let it be done unto me according to your word” (Luke 1:38), made the Divine Incarnation of Jesus possible. Jesus enters the redemptive suffering of His Passion with his obedient surrender to His Heavenly Father “non mea voluntas, sed Tua fiat” or “Not my will but Yours be done” in the Garden of Gethsemane (Luke 22: 42). Jesus also prefigures The Fiat of Sanctification when He implored the coming of the Kingdom, in the ‘Our Father’, the only prayer He taught His disciples “Fiat voluntas tua, sicut in Coelo et in terra” or Your will be done on earth as it is in heaven (Matthew 6:10). We believe this period of great sanctity prophesied and promised has been ushered in with Jesus’ greatest of graces: the gift of Living in His Divine Will.