The preaching of the Word of God does not go out or return void, despite what we might witness or think otherwise. The Sacred Word continues to convict the heart and give new life to all who are dead in iniquity.
Fellow under-shepherd, I've been there. I know the frustration you feel when it seems that you preached your heart out this past Sunday, feeding your flock the food of the Word and proclaiming the message God placed upon you. I know what it means to study for long hours, to pray, to compose