There are a number of good points of reference, but some I would begin with would be 2 Peter 1:3-4: "His divine power has granted to us all things that pertain to life and godliness, through the knowledge of Him Who called us to His own glory and excellence, by which He has granted to us His precious and very great promises, that through these you may escape from the corruption that is in the world because of passion, and become partakers of the divine nature." In the same vein, St. John writes: "See what love the Father has given us, that we should become children of God; and so we are....Beloved, we are God's children now; it does not yet appear what we shall be, but we know that when He appears we shall be like Him, for we shall see Him as He is" (1 Jn 3:1-2). Both Peter and John go on in these passages to describe the moral discipline requisite upon such a hope, the hope of union with God. God had said to Moses, "you cannot see My face; for man shall not see Me and live" (Ex 33:20). But now, according to the New Testament, this vision of God that is beyond human capacity is offered to humanity, who by virtue of their union with Christ find themselves caught up into the union of His person, the union of the divine and human natures.
I think that in this light, many Scriptures that speak of this union with Jesus will apply. Ephesians 5:25-32 comes to mind:
Husbands, love your wives, as Christ loved the Church...husbands should love their wives as their own bodies. He who loves his wife loves himself. For no man ever hates his own flesh, but nourishes it and cherishes it, as Christ does the Church, because we are members of His body. "For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh." This is a great mystery, and I mean in reference to Christ and the Church...(cf. Gn 2:24)
In this vein one might read, as it has often been read, The Song of Solomon as a poem not merely of human love, but of the love of God for the human soul. And of course the aim, quite expressly, of the entire Song is not merely one of contemplation or exchange of vows, but the union of persons, of the lover and the beloved. This union of God and man, achieved in the Incarnation, is extended to Christians who are by union with Christ made children of God (cf. Rom 6:1-14, 8:9-17), and we hope ultimately to see Him face to face. Thus, according to St. Paul, "I consider that the sufferings of this present time are not worth comparing with the glory that is to be revealed to us," and even "the creation waits with eager longing for the revealing of the sons of God" (Rom 8:18-19; cf. 1 Cor 15:28), and Jesus Himself prays to the Father on the eve of His crucifixion: "The glory which You have Given Me I have given to them...Father, I desire that they also, whom You have given Me, may be with Me where I am, to behold My glory which You have given Me in Your love for Me before the foundation of the world" (Jn 17:22,24).
A thread of "fulness" runs from the biblical description of Jesus as He in Whom "the whole fulness of deity dwells bodily" (Col 2:9), to the description of the Church as "His body, the fulness of Him Who fills all in all" (Eph 1:23), to the future hope which even creation itself joins in anticipating, "when all things are subjected to Him, [when] the Son Himself will also be subjected to Him Who put all things under Him, that God may be all in all" (1 Cor 15:28). This "fulness" is not unrelated to the fulness of grace attributed to Mary, in whom the Scriptures see a uniquely excellent fulfillment of God's exchange of love with a human person (cf. Lk 1:26-56, etc). For Mary this exchange has all the reality of pregnancy, motherhood, widowhood, bereavement, and all that she underwent and contributed throughout her life with Jesus, God her Son.
An excellent resource on this is Called to Be the Children of God: The Catholic Theology of Human Deification, edited by Fr. David Meconi and Carl E. Olson, particularly the first essay, contributed by the editors, "The Scriptural Roots of Christian Deification."
I hope this helps!
