The Bible gives simple answers to this question. Unfortunately, false ideas about important biblical concepts like repentance, faith, and original sin have crept into the church over the years. So those simple answers often do not suffice, and more involved answers need to be given. Simple Answer #1 The apostle Peter preached to a crowd on Pentecost and told them (Acts 2:38–39): Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit. The promise is for you and your children and for all who are far off—for all whom the Lord our God will call. This is probably the simplest and clearest passage in Scripture that tells us whom baptism is for. It is for a) adults who hear God’s word and repent—that is, acknowledge their sinfulness and trust in God for forgiveness in the name of his Son Jesus—and b) the children of such adults. Simple Answer #2 Infant baptism is established by two facts, namely a) that infants, like everyone else, need to be saved from sin, death, and hell by God, and b) that God saves people through baptism. These Bible passages clearly proclaim both of those truths: Certainly, I was guilty when I was born. I was sinful when my mother conceived me.—Psalm 51:5 Jesus answered, “I tell you the truth, no one can enter the kingdom of God unless he is born of water and the Spirit. Flesh gives birth to flesh, but the Spirit gives birth to spirit.”—John 3:5–6 And corresponding to that [namely the water of the flood through which Noah and his family were saved], baptism now saves you—not the removal of dirt from the body but the guarantee of a good conscience before God through the resurrection of Jesus Christ.—1 Peter 3:21 Simple Answer #3 Because of both of the simple answers above, infant baptism was the standard practice in the Christian church from the time of the apostles up until the time of the Reformation in the 1500s. The apostles baptized entire households (Acts 16:15, 33–34; 1 Cor. 1:16). A Christian bishop named Cyprian wrote to a fellow bishop named Fidus around 252 AD (Epistle 58): But with respect to the case of the infants, which you say ought not to be baptized within the second or third day after their birth, and that the law of ancient circumcision should be regarded, so that you think that one who has just been born should not be baptized and sanctified before the eighth day, we all [namely, Cyprian and sixty-five other bishops] thought very differently in our council. For no one agreed with the course you thought should be taken. We all rather judge that the mercy and grace of God should not be refused to anyone born of man. Note that, even though Fidus held an incorrect view, he too was in favor of infant baptism, just not before the eighth day. Many who reject infant baptism will appeal to the early Christian author Tertullian. It is true that Tertullian wrote a treatise On Baptism around 193 AD in which he advised the delay of baptism, especially in the case of little children (Chapter 18). However, it is important to note: Tertullian’s opinion is only his own. Compare that to the judgment of Cyprian above, which had the support of sixty-five other Christian bishops. Even as he is objecting to infant baptism, Tertullian acknowledges that it is, in fact, the ordinary Christian practice. He even says that Christians are “hastening” to have their infants baptized. He also mentions sponsors, which implies that the practice of having one or more adults sponsor an infant at his/her baptism was already in place. Even when Christians postponed baptism until later in life in unique cases, like Augustine, they did so not for the reasons that are cited today, but because they erroneously thought that baptism only cleansed the sin that one had committed up to that point. So they still acknowledged it as a sacrament through which God washed away sin; they were just mistaken as to the extent of its effectiveness. So a person who rejects infant baptism will have to take the problematic position that Christians on the whole didn’t understand baptism or use it correctly until the 1500s—even though the early Christians were the ones who had Jesus’s teaching handed down to them from the apostles and their disciples. Detailed Answer Click here for a more comprehensive scriptural explanation of why we baptize infants.