The Exaposteilarion of today's Feast declares: "Verily, the Creator of ages Who fulfilled the law is circumcised in the flesh as an eight-day old child, is wrapped in swaddling clothes like a man and is fed with milk, He Who is the All-Controller through His boundless might, since He is God, and the Maker of the law in flesh."
Observe the wording of declaration: "the Creator of the ages...fulfilled the law." The statements that follow concerning His circumcision, clothing as a man, and being fed milk, appear to specify ways in which He fulfills the law in concrete terms. How are we to understand these actions as fulfillment? What is filled full, put into effect, brought to an end, satisfied, converted into reality or brought to its potential?
The "laws" of the created order require infants to be fed and clothed for survival, yet the Lord Who is unbounded and is eternally free from any need for protection has chosen to take our flesh upon Himself, for He is God the Word assuming the limitations and demands of the natural law. Therefore, He was diapered and nursed. Observe that His satisfaction of the natural law is expressed in many of the icons of the Nativity for they regularly show Him being washed and cared for as well as being "wrapped...in swaddling cloths" (Lk. 2:7).
These most mundane, human actions direct us to the Apostle Paul's point: when the Lord was "found in appearance as a man, He humbled Himself," lowered Himself in every respect (Phil. 2:7). In other words, He came into the world and joined Himself to us an actual man in order to address the terrible side of being human: separation from God and our wedding to death.