"...what you have heard from me in the presence of many witnesses entrust to faithful men, who will be able to teach others also"
-2 Timothy 2:2
The greatest investment you can make is in your own personal relationship with God through Jesus Christ. The next greatest investment you can make is in someone else's personal relationship with God though Jesus Christ. How are you investing?
"Only one life, 'twill soon be past;
Only what's done for Christ will last."