Read Acts 2:41. How is baptism spoken of here as the sign of entrance into God's church?
Then they that gladly received His Word were baptized: and the same day there were added unto them about three thousand souls.
In whom also ye are circumcised with the circumcision made without hands, in putting off the body of sins of the flesh by the circumcision of Christ:
Buried with Him in baptism, wherein also ye are risen with Him through the faith of the operation of God, who hath raised Him from the dead.
For we are the circumcision, which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh.
How are the realities of both New Testament baptism and the Lord's Supper related to the Old
Testament church in I Corinthians 10: 1-4?
Moreover, brethren, I
would not that ye should be ignorant, how that all our fathers were under the cloud, and all passed through the sea;
And were all baptized unto Moses in the cloud and in the sea;
And did all eat the same spiritual meat;
And did all drink the same spiritual drink: for they drank of that spiritual Rock that followed them: and that Rock was Christ.
-I Corinthians 10: 1-4
Paedo-baptism -Infant and child baptism
"the putting off the body of the sins of the flesh"; the same spiritual picture is portrayed in baptism -the death (burial) of the old, sinful nature and enlivening of the new, holy nature. Both rites are linked in the same two verses picturing the same spiritual death (old man) and resurrection (new man) through the power of the risen Savior. "In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: buried with Him by baptism, wherein also ye are risen with Him through the faith of the operation of God, who hath raised Him from the dead" (Colossians 2:11-12).
How were the uncircumcised Colossian believers "circumcised" (verse II)? They were circumcised spiritually in Christ, of which their baptism was a sign and seal (verse 12).
Paul also tells the uncircumcised but baptized Philippian church, "For we are the circumcision, which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh" (Philippians 3:3).
These direct links are written by the same apostle who taught that the circumcision rite had ended, that it no longer had a special sacramental meaning, "For in Christ Jesus neither circumcision availeth anything, nor uncircumcision, but a new creature" (Galatians 6:15). (For additional references, see Acts 15:5-29; Romans 2:25-28, 3:30, 4:9-11; I Corinthians 7:18-19; Galatians 2:3-4,5:2-11,6:12-15; Ephesians 2:11,15; Colossians 2:11 and 3:11.)
With these four truths, Scripture establishes the fact that New Testament baptism replaced Old Testament circumcision. Therefore, objections to paedo-baptism on the grounds that infants cannot understand that which is taking place or that they cannot exercise faith when being baptized, are dismissed by God Himself. God commanded eight-day-old infants to be circumcised; neither could they understand or exercise faith in that which was taking place. Yet God commanded them to be circumcised in their infancy. Since baptism replaced circumcision, without a change of directions regarding its proper recipients being received from the Lord, infants are to be baptized -to bear the sign of God's covenant and church.