Over the years, I've had many friends who are Christian, but not Lutheran, and generally, this means we have a different view of baptism. Usually, it means that they have an objection to one of two things, or both: 1). That a child is baptized without first declaring their faith. 2). (which is a variant) that the child did not have a choice in the matter.
Sometimes they state that there is nothing in the Bible that specifically says to baptize infants. Often, we as Lutherans point to Christ's "Suffer not the little children to come unto me" with the Greek word for children meaning "infant." Also, it says to baptize nations, Acts records entire households being baptized, and of course, Paul's declaring baptism to be the new circumcision, with circumcision being on the 8th day of life.
Lutherans also point to the verse "No man can come to the Spirit unless the Holy Spirit draws Him" and other such verses that shape our doctrine that we do not choose Christ, Christ chooses us. We cannot come to faith through our own understanding but only through the Holy Spirit. One way we receive the Holy Spirit is through baptism, and there is proof in the Bible that infants can have the Holy Spirit and faith - John the Baptist danced in Elizabeth's womb when Mary, newly pregnant with the Messiah, came near.
I don't ever remember seeing a place in the Bible where a child comes to a particular age and chooses his faith or direction in that faith. Just as we cannot choose our status as sinners, those of us brought up in the faith cannot choose our status as believers, either. The Bible is full of examples of this.
Some that come to mind for me are:
Noah's children -- Even though they are clearly grown at this point, it never says that they are welcome on the ark because of their own faith, but because of Noah's.
Descendants of Abraham -- Isaac did not offer to be a sacrifice or to be the one to procure the line of Abraham into a great nation. In fact, when Sarah took it into her own hands to help along God's promise of giving him an heir, God rejected it. Joseph surely didn't choose to be sent to Egypt, yet God used him mightily. The children of Israel were God's people not because they were worthy of it and constantly choosing to be loyal - God chose them, and He was the one continually keeping that covenant alive.
When God rescued the Israelites from Egypt, he led them through the Red Sea...baptizing them as His own as they walked through it. Yet, He didn't say, those of you who want to come, come forth. He led them through, young and old, weak and strong, those with faith and those who didn't. He brought them through the desert and to the Promised Land.
Infants and grownups alike made this journey, infants and grownups alike celebrated the Passover and other feasts, and the instruction from Scripture was to tell the children why they do this as they ask and to raise them to know God.
Samuel didn't chose to serve in the tabernacle or to be a prophet. Hannah decided his life for him before he was even conceived, and God took him as his prophet. David didn't choose to be king, but he faithfully served God. No prince to follow would choose either.
I'm just going through and listing things that come to mind, and looking at the Bible, a first born son was presented soon after he was born and the atoning sacrifice made for him. All boys were circumcised on the 8th day. They were brought into the covenant, not choosing to participate in it...and Paul clearly states that baptism is the new circumcision.
Basically, in this argument, we are often put on the defensive. When the world says "prove to me that we are to baptize infants" we need to say "prove to me that we are not supposed to." Because it isn't there. It just isn't. There are words that often embrace infants - nations, households, families, children...these are to be included in baptism. The Jewish faith includes infants in the covenant. Yet Evangelicals state "no..you have to confess your faith before you engage in this symbolic act." We need to say "but where does it say that in Scripture?" and "Where does it say that it is merely symbolic?"
I'd love to find out what is the argument and the history behind excluding infants and young children from being one in the death and resurrection of Christ, to find why they don't need it, why they wouldn't want us to give that to them, when they welcome God's gifts that sustain their lives, which flow through us their parents, in every other way.