“While Peter yet spake these words, the Holy Ghost fell on all them which heard the word. And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost. For they heard them speak with tongues, and magnify God. Then answered Peter, Can any man forbid water, that these should not be baptized, which have received the Holy Ghost as well as we?” (Acts 10:44-47)

Circumcision served as the sign or symbol of the Old Covenant (Genesis 17:9-11; Exodus 12:43-48; Leviticus 12:3; Joshua 5:1-9). By being circumcised, men, along with their male offspring, consecrated themselves to God and identified themselves with the people of God. All who refused to be circumcised were excluded from the ranks of God’s chosen people.

To show the seriousness of circumcision, the Bible relates a curious incident from the life of Moses (Exodus 4:24-26). Apparently, Moses had refused to circumcise his son over the objection of the boy’s mother, Zipporah, who was not a Hebrew, but a Midianite. Because of this dereliction of Moses’ covenant obligation in regards to his son, God was about to kill Moses on his return trip to Egypt. Moses’ life was saved, however, by the intervention of his wife Zipporah. Although she was obviously not happy about it, Zipporah circumcised her son in order to save her husband. 

As circumcision was the sign of the Old Covenant, baptism is the sign or symbol of the New Covenant. Believers show their consecration to Christ and identification with His church by being baptized. Why should anyone refusing to be baptized be included in the membership of your local church, which is part of the new “Israel of God” (Galatians 6:16)? Obviously, they, like those refusing to be circumcised in the Old Covenant, should be excluded from the ranks of God’s chosen people, due to their unwillingness to prove their consecration to Christ and identification with His church.

Is there any reason to believe that God takes baptism—the sign of the New Covenant—any less seriously than He did circumcision—the sign of the Old Covenant? Since the New Covenant is a better covenant with better promises (Hebrews 8:6), there is every reason to believe that God takes baptism every bit as seriously as He did circumcision, if not more so. Although the New Testament contains no incident concerning one’s refusal to be baptized that is comparable to Moses’ refusal to circumcise his son, it does  teach us that many have ended up in premature graves due to their failure to properly observe the other ordinance of the church—the Lord’s Supper (1 Corinthians 11:30).

“Circumcision was [a] sign of personal faith…the outward seal that was given to show the individual's faith…This, of course, is exactly what baptism is in the New Testament…Old Testament circumcision was what baptism is in the New Testament.” (Francis Schaeffer)