Gal 4:4-7
"But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, ‘Abba! Father!’"
The 'fullness of time' (pleroma tou chronou): the historical moment prepared by God — Pax Romana, common Greek language, Roman roads, Jewish dispersion. Adoption (hyiothesia) is the result of redemption. The Spirit crying 'Abba, Father' is the evidence of adoption.