The origin of a divine person from another through the communication of the numerically one divine essence. There are two internal processions in the Trinity: the begetting of the Son from the Father, and the procession of the Holy Spirit from the Father and the Son. It is divine persons, not the divine nature, who are the subjects of the internal divine procession. The second divine person proceeds from the intellect of the first divine person by generation, and therefore is related to him as Son to a Father. The third divine person proceeds from the will or mutual love of the Father and the Son as from a single principle through spiration.