Your purpose is far beyond those who have no Lord.
The purpose should be to know and serve Him. It should permeate each decision and override any out of control tendency in the thought life.
Your purpose should drive you to the Word and should give impetus for prayer when it feels like prayer is too hard or not possible.
Your purpose should censor your language and release your tongue to the Lord's creativity.
Your purpose should give you the ability to continue when exhausted, to sing in the darkest nights, to declare eternal reality in the face of conditions that defy faith and to love the unlovely.
Your purpose releases you. You are no longer your own.
What freedom!