Confirmation is in some sense to fulfilment of Baptism. For a long time we understood that as Children our Parents and Godparents made promises on our behalf and in confirmation, now being of an age when we might speak for ourselves we might Confirm the promises that were made on our behalf. However it is also a time when the Bishop, representing the fullness of the connect with the Church of the Apostles might in the name of that Church confirm Christ's promises to us. 

Strengthen, Lord, your servant with your Holy Spirit
Empower and sustain them in your service

Defend, O Lord, you servants with your heavenly grace,
that they may continue yours for ever
and daily increase in your Holy Spirit more and more
until they come to your everlasting Kingdom. Amen.

Like Baptism, Confirmation is a journey sacrament, and marker on the what to what we are becomming.