Many times, ministers don't get to see the full impact of their ministry. I often times hear preachers talk about the people who had encouraged them, and the words and wisdom that they gave. The words that were spoken several years ago are still ministering to people today.
1st Thessalonians 1:8
For from you the word of the Lord has sounded forth, not only in Macedonia and Achaia, but also in every place. Your faith toward God has gone out, so that we do not need to say anything.
What we say and do today has the power to impact the lives of future generations. Send forth the word of the Lord, that others may hear, and and send it forth.