"But Jesus said, Suffer little children, and forbid them not, to come unto me: for such is the kingdom of Heaven." (Matt. 19:14)
"Holy Baptism is the basis of the whole Christian life, the gateway to life in the Spirit, and the door which gives access to the other sacraments. Through Baptism we are freed from sin and reborn sons of God; we become members of Christ, are incorporated into the Church and made sharers in her mission: "Baptism is the sacrament of regeneration through water in the word." (Cathecism of the Catholic Church (c) 1995)
When I studied infant baptism in highschool (I went to a Catholic private school) I was taught that my 'baptism' at that point was an indelible mark. Infant baptism is percieved as necessesary because of the idea that it erases 'original sin.'
Some facts to consider: 1. Faith alone justifies (Rom. 3:26) . 2. Everyone who ever got baptized in the New Testament excersized faith first, infants cannot do this (Acts 2:41; 8:36-38; 9:15-18; 10:44-47; 16:14-15, 30-34). 3. Jesus laid his hands on these children, he did not baptize them, in fact He did not baptize anyone (John 4:2).