What is more, I'm convinced from Scripture that it is not we who baptize infants who must prove the biblical right to do so, but those who refuse to baptize them.

Look at Jesus' simple words in his command to baptize. He speaks very generally as he urges us to make disciples of ALL NATIONS by baptizing and teaching (Matthew 28:19). When we baptize people of all ages, including infants, are they not clearly a part of all nations? If Jesus had meant to limit baptism only to those who were older, why did he not clearly state that instead of speaking with such a sweeping phrase as "all nations"?

If someone is going to make an exception to Jesus' words (such as those do who refuse to baptize infants), they better have a clear Scriptural reference that makes that exception. Lacking any such passage, we are perfectly in line with Scripture to baptize people of all nations--including infants. It is not we who baptize infants who have the burden of proof. It is those who do not baptize infants.

Add to that simple truth the doctrine of original sin that you mentioned. We are already sinful from the time we are conceived (Psalm 51:5). The Apostle Paul tells us that we are "by nature objects of wrath" (Ephesians 2:3).

Although from what we can tell, infants are not fully conscious of their sinful state, it is not "consciousness" of our sinfulness that makes us guilty before God. We are guilty whether we are aware of our sin or not (Psalm 19:12). We are held responsible before God for the fact that we are the sinful offspring of sinful parents, whose very nature is one of hostility toward God (John 3:6; Romans 8:7). Infants, just like the rest of us, stand in desperate need of the forgiveness of sins in Jesus--even though they may not be sinning consciously and knowingly. Therefore, they have just as real a need for the forgiveness offered in baptism as we do.

Often, a further objection to infant baptism comes from those who believe faith is a "decision" of man rather than merely trust in the heart worked by the Holy Spirit as God's gift. If faith were some kind of decision man must make, of course infants couldn't have such "faith." But faith is indeed a gift of God worked alone by the Holy Spirit. That miracle of faith (compared in Scripture to our first birth) is worked by the Holy Spirit in hearts touched by Word and Sacraments (Ephesians 2:8,9; 1 Corinthians 2:14; John 3:5,6, Titus 3:5,6).

Although it is true that there is no specific mention of any particular infant baptism in the New Testament, yet it is also interesting to consider the importance of the Greek word for "household" that is used in the context of baptism in Acts 16 (both in connection with the households of Lydia and the jailer of Philippi) and 1 Corinthians 1 (in connection with the household of Stephanas). The Greek word for household was used to include people of several generations--young and old--who shared a common home. In wealthy families--as Lydia's clearly was--that would often include several generations of servants and slaves who were considered a part of that household. The household could be a very significant number of people of all ages. That Greek word for household is never used in any context in the New Testament that would exclude children. The least we could say about that is that it would have been careless for the Holy Spirit to use that word in connection with baptism if indeed the Scriptures were forbidding infant baptism.