Adoption as Children of God

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It’s no mere legality! It is a matter of flesh and blood, just like human adoption, except it gives us an even closer relationship than that to God. St. Nicholas Cabasilas explains (pp. 127-128):

This is the reality of our adoption as sons of God. Unlike human adoptions, it does not consist in the mere name, nor does it confer honour merely to the extent that those who have been adopted share the name of those who have been naturally born…In this case…there is a real birth and a sharing with the only-begotten Son, not of the surname only, but of His very Being, His Blood, His Body, His life…

Why then should I call this sonship fictitious, when it makes us more alike in nature and more closely akin than natural sonship? … What is it that makes men our true fathers? It is the fact that our flesh is derived from theirs, and our life is produced from their blood. This applies to the Saviour as well. We are flesh from His flesh and bones from His bones. Yet there is a considerable difference between these two participations. In the case of the natural sons, their blood no longer belongs to their parents, though it was theirs before it became that of the sons. So kinship arises from the fact that what once belonged to the parents now belongs to the offspring. But the effect of the sacred rite [the Eucharist] is that the blood by which we live is even now Christ’s Blood, and the flesh by which the Mystery establishes us is Christ’s Body, and further, that we have members and life in common with Him.

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St. Nicholas Cabasilas goes on to explain that if something belongs to one person part of the time and to another person the rest of the time, then it is not as truly shared as when it belongs to both people simultaneously. The Body and the Blood of Christ (unlike the body and blood of our natural parents) belong both to Him and to us at one and the same time. That makes us, even at the bodily level, closer to Him than to our own parents.