There are a great many labels thrown around about this subject: believer's baptism, infant baptism, Spirit baptism, etc. But Christians, specifically Lutherans, don't stand for any of these in particular. We stand for Baptism, plain and simple, in all of its Biblical glory.
You might object that Lutherans are always talking about the importance of baptizing infants, and this is true. But to reduce the Sacrament to this argument is too simplistic.
Baptism is commanded by Christ for the making of disciples (Matthew 28:19). It is not optional. And there is only one baptism, as Saint Paul tells us in Ephesians 4:5.
With this one baptism the Holy Spirit washes away our sins (Titus 3:5), and unites us with the death and resurrection of Jesus Christ (Romans 6:3-5), effectively guaranteeing our own resurrection to glory on the Last Day.
This is all done by the work of God. We have nothing to do with it. It is an objective application of the grace of God directly to our lives.
Faith is important in baptism. Faith receives the gift. Baptism, by God's power, elicits faith from the newly regenerated person, faith in Christ Jesus.
Yet faith does not make the baptism valid. Then it would depend upon me and my strength of faith, rather than on the power of God.
One Lord, one faith, one baptism! Here we stand!
[Tomorrow: We stand for the Lord's Supper!]