Hebrew אב, “father.” The masculine sexual power of the Holy Spirit, the sephirah Binah ("understanding"), accompanied by Aima, the feminine sexual power of Binah.
Abba the Father of Shechinah (feminine Hebrew word that means “the dwelling of the presence of God" - the sephirah Chesed, "mercy"), Gedulah is fecundated by the Holy Spirit Binah (Jehovah Elohim) within the womb of Aima Elohim. He controls the creation of the lower sephiroth by means of Daath ("knowledge"). Thereafter, he may impregnate the womb of Aima Elohim in order for Chokmah (as the Son of Man, Christ) to be born within the bodhisattva.
“Abba, Father, all things are possible unto thee; take away this cup from me: nevertheless not what I will, but what thou wilt.” - Mark 14:36