Worship Elements: You and Your Children (Acts 2:39)

Peter takes his stand in the midst of the skeptics in Jerusalem.  Peter makes the point that the Lord was sent to the cross by these wicked men who listen to Peter’s sermon.   What does baptism have to do with Christ’s mission and the reception of the Holy Spirit?  Does Baptism have any correlation to the Old Testament?  Why does Peter say that the promise is for you and your children?