Irenaeus — Against Heresies 5.8.1
But now we receive some portion from his Spirit, toward perfection and preparation for incorruption, gradually becoming accustomed to receive and carry God — which the Apostle also called a pledge…
If therefore, now having the pledge, we cry “Abba, Father,” what will it be when, rising, we see him face to face…? For if the pledge, embracing the human being into itself, already makes us say “Abba, Father,” what will the whole grace of the Spirit do, which will be given to human beings by God? It will make us like him, and will perfect us by the Father’s will; for it will make the human being according to the image and likeness of God.
Latin
Nunc autem partem aliquam a Spiritu ejus sumimus, ad perfectionem et praeparationem incorruptele, paulatim assuescentes capere et portare Deum: quod et pignus dixit Apostolus… Si igitur nunc pignus habentes clamamus, Abba Pater; quid fiet quando resurgentes faciem ad faciem videbimus eum… Si enim pignus complectens hominem in semetipsum, jam facit dicere, Abba Pater, quid faciet universa Spiritus gratia, quae hominibus dabitur a Deo? similes nos ei efficiet, et perficiet voluntate Patris; efficiet enim hominem secundum imaginem et similitudinem Dei.