M'r:16:15, 16: And he said unto them, Go ye into all the world, and preach the gospel to every creature. He that believeth and is baptized shall be saved; but he that believeth not shall be damned.

In M'r:10:13 – 16 the Lord Himself sets before us that infants are role models of those fit to receive the Kingdom. And for this reason the elderly need to convert (hear & believe) and become like children.

M'r:10:13 - 16: And they brought young children to him, that he should touch them: and his disciples rebuked those that brought them. But when Jesus saw it, he was much displeased, and said unto them, Suffer the little children to come unto me, and forbid them not: for of such is the kingdom of God. Verily I say unto you, Whosoever shall not receive the kingdom of God as a little child, he shall not enter therein. And he took them up in his arms, put his hands upon them, and blessed them.

Here the Lord points out those who are to receive the Kingdom, children or infants and the elderly who are willing to becomes as children.. Who is man to ‘forbid’ those who are openly stated by the Lord to be ‘of the Kingdom’ and that ‘that born flesh is flesh and Spirit is Spirit’. Thus permit them to be baptized to receive the Spirit just as those who convert to children are permitted.

Children are holy enough to receive the Kingdom, while the elderly need to repent and believe (convert and become as children) to receive the Kingdom. The elderly were called to ‘convert’.

M'r:4:12: That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them.

In the New Testament, no doubt adults are called to repent and believe (or convert as children) before they are to be baptized (or to receive the Kingdom). If one is unbaptized as an adult, one does not baptize him unless he believes. Also, one who is baptized as an infant, when he reaches the age of reason, must come to believe in Jesus. The Catholic Church does affirm the necessity of believing in Jesus when one reaches the age of reason. However, the grace that is given in infant baptism makes it easier for him to come to the conclusion that Jesus is Lord, than one without that grace given at baptism. The child who is baptized as an infant should be nurtured in the faith, no doubt. All parents are commanded to “Train up a child in the way he should go, and when he is old he will not depart from it”, Proverbs 22:6 ; Eph 6:4 Infant Baptism is indeed Biblical, and one should never forbid the Children from entering the covenant established by Christ. After all, Jesus did say, “Let the little children come to me, and do not forbid them, for of such is the kingdom of heaven.”(Mt. 19:14)

When arguing about if we need to believe first and then be baptized, everyone forgets about the one who paved the way or ‘made straight the path’ for the New Testament to come to being i.e. John the Baptist (Luke 1:17). We forget that he was born of the Holy Spirit ‘even in his mother’s womb’, as the Bible says in Luke 1:15. He is called the ‘greatest among them that are born of women’ (Matt 11:11).

And what of the one whom the Bible sets as the perfect example of faith; father Abraham and Isaac his son. Abraham believed and received the ‘promise’ while Isaac was heir to the promise even before being born. See But did not Abraham believe and was afterwards circumcised

But did not Abraham believe and was afterwards circumcised?

Yes, but his son Isaac was circumcised when 8 days old on the belief of his father Abraham.

Abraham believed and circumcised his 13 year old elder son Ishmael and the male servants  on his belief in God. The Bible says,

Ge:17:23-27: And Abraham took Ishmael his son, and all that were born in his house, and all that were bought with his money, every male among the men of Abraham's house; and circumcised the flesh of their foreskin in the selfsame day, as God had said unto him. And Abraham was ninety years old and nine, when he was circumcised in the flesh of his foreskin. And Ishmael his son was thirteen years old, when he was circumcised in the flesh of his foreskin. In the selfsame day was Abraham circumcised, and Ishmael his son. And all the men of his house, born in the house, and bought with money of the stranger, were circumcised with him.

Ge:21:4: And Abraham circumcised his son Isaac being eight days old, as God had commanded him.

Ac:7:8: And he gave him the covenant of circumcision: and so Abraham begat Isaac, and circumcised him the eighth day; and Isaac begat Jacob; and Jacob begat the twelve patriarchs

Ga:4:28: Now we, brethren, as Isaac was, are the children of promise.

Ro:9:4: Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;Ro:9:5: Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen.Ro:9:6: Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel:Ro:9:7: Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called. Ro:9:8: That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed. Ro:9:9: For this is the word of promise, At this time will I come, and Sara shall have a son. Ro:9:10: And not only this; but when Rebecca also had conceived by one, even by our father Isaac; Ro:9:11: (For the children being not yet born, neither having done any good or evil, that the purpose of God according to election might stand, not of works, but of him that calleth;)

Abraham received the ‘promise’ after he believed God while Isaac his son received the heirship to the promise before his birth.

Ac:2:39: For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call.

In the Old Testament, if a man wanted to become a Jew, he had to believe in the God of Israel and be circumcised. In the New Testament, if one wants to become a Christian, one must believe in God and Jesus and be baptized. In the Old Testament, those born into Jewish households could be circumcised in anticipation of the Jewish faith in which they would be raised. Thus in the New Testament, those born in Christian households can be baptized in anticipation of the Christian faith in which they will be raised. The pattern is the same: If one is an adult, one must have faith before receiving the rite of membership; if one is a child too young to have faith, one may be given the rite of membership in the knowledge that one will be raised in the faith.

The same was true of circumcision; faith in the Lord was necessary for an adult convert to receive it, but it was not necessary for the children of believers.

The children have no say here but to adhere to what the parents perform.

Did the believers in the Bible actually have a deep insight of Christian belief before their going through the sacrament of baptism?

Ac:19:2: He said unto them, Have ye received the Holy Ghost since ye believed? And they said unto him, We have not so much as heard whether there be any Holy Ghost.

The believers not just one or two but the church in Samaria the Bible says ‘have not so much as heard whether there be any Holy Spirit’.

CONVERSION (BAPTISM) IN THE OLD TESTAMENT - MIKVEH

According to Jewish law there are three basic areas where immersion in the baptismal water mikveh is required.

1. Immersion is required for both men and women when converting to Judaism. There were three prerequisites for a proselyte coming into Judaism: Circumcision, baptism, and sacrifice (Maimonides, Hilkh. Iss. Biah xiii. 5).

2. Immersion is required after a woman has her monthly period (Lev.

Although it is the Jewish belief that repentance is necessary, purification from defilement is done primarily through water, while other effects of sins are covered by blood (Romans 4:7; note the "almost all things" in Hebrews 9:22).

A convert would reaffirm his acceptance of the Torah by declaring, "I will do and I will hear" which was a phrase from the oath that was originally taken by the priests not to forsake the Torah (Deuteronomy 29:9- 14). This ritual demonstrates the willingness of the convert to forsake his Gentile background and assume his Jewish identity by taking on the status of one who keeps the commandments.

The baptismal water (Mikveh) in rabbinic literature was referred to as the womb of the world, and as a convert came out of the water it was considered a new birth separating him from the pagan world. As the convert came out of these waters his status was changed and he was referred to as "a little child just born" or "a child of one day" (Yeb. 22a; 48b; 97b). We see the New Testament using similar Jewish terms as "born anew," "new creation," and "born from above."

We are told, by men learned in Jewish antiquities, that, under the Old Testament economy, it was customary, when proselytes to Judaism were gained from the surrounding nations (M't:23:15, Ac:2:10, Ac:6:5, Ac:13:43), that all the children of a family were invariably admitted to membership in the church with their parents; and on the faith of their parents; that all the males, children and adults, were circumcised, and the whole family, male and female, baptized, and incorporated with the community of God's covenanted people.[1] Accordingly, when we examine the New Testament history, we find that under the ministry of the apostles, who were all native Jews, and had, of course, been long accustomed to this practice, the same principle of receiving and baptizing families on the faith of the parents, was most evidently adopted and acted upon in a very striking manner. When "the heart of Lydia was opened, so that she attended to the things which were spoken by Paul," we are told that "she was baptized and her household" (Acts 16:14-15). When the jailor at Philippi believed, he was baptized, "he and all his, straightway" (Acts 16:33). Thus also we read of "the household of Stephanas" being baptized (1 Cor. 1:16). Now, though we are not certain that there were young children in any of these families, it is highly probable there were. At any rate, the great principle of family baptism of receiving all the younger members of households on the faith of their domestic head, seems to be plainly and decisively established. This furnishes ground on which the advocate of infant baptism may stand with unwavering confidence. 

Christ Reigns!!