All prayer should have the glory of God as its chief aim. Amen is our YES to the glory of God. Prayer is laying hold onto promises. Prayer is drawing on the account where God has deposited all his promises. Prayer is not hoping in the dark that there might be a God of good intentions out there.
Prayer goes to the bank and draws on promises.
Which leads to . . . AMEN is a full and precious word in times of prayer. AMEN means, YES, Lord you can do it. It means, YES, Lord, you are powerful. YES, Lord, you are wise.