We were born as human beings and we have been born again as children of God. First Peter 1:23 says that we have “been regenerated…through the living and abiding word of God.” Because of this spiritual birth, 1 Peter 2:2-3 continues:
As newborn babes, long for the guileless milk of the word in order that by it you may grow unto salvation, if you have tasted that the Lord is good.
When we were born of God, we received God in Jesus Christ as our new life. Now, just as human babies need milk for their growth, we need the milk of the word that we may grow. This growth is the development of Christ as our life in us. Verses 2:4-5 go on to say,
Coming to Him, a living stone, rejected by men but with God chosen and precious, you yourselves also, as living stones, are being built up as a spiritual house into a holy priesthood to offer up spiritual sacrifices acceptable to God through Jesus Christ.
Our drinking of the milk and our tasting the Lord is our coming to Him. He is the “living stone” who makes us “living stones.” The more we come to Him, the more life increases in us. By this life we “are being built up” and the result is “a spiritual house.” This matches the revelation throughout the New Testament that building is not physical but spiritual. Let us continue “coming to Him.” Verse 6 continues:
For it is contained in Scripture: “Behold, I lay in Zion a cornerstone, chosen and precious; and he who believes on Him shall by no means be put to shame.”
Jesus Christ Himself is the cornerstone of this building. Our believing on Him brings us to Him not only for life but also for this building. While we grow in this life the building work is progressing. Ultimately the building will become New Jerusalem.