Your service is where you are at.  No matter your calling, your service is what you do with every hour of life that God gives you.  Whether it is taking kids to school or working to support a family or being a Pastor of a congregation, each is serving God.  With each there is also opportunity to share through action and works the saving Grace of Christ to all those we come in contact.  On my flight from Baton Rouge to Paris sitting next to a young man on his way to Dubai our conversation gravitated to God's work and His simple message of salvation.  He just happened to have his "most important day of his life" coincide with my last minute trip and sat right next to me for 10 hours of flight. It really was "the most important day of his life” because he heard the message of Salvation. Then there was the English chauffeur driving me from Heathrow to South Hampton that just happened to be struggling with the question of God and his religious fiancée. He also thanked me for taking the opportunity to share with him on that 30 minute limo ride.