"And what you have heard from me in the presence of many witnesses, commit to faithful men who will be able to teach others also."
-2 Timothy 2:2
The Great Commission is all about discipleship! In fact, I would argue that you couldn't separate evangelism and discipleship. The sweet, I preach don how God uses us all. If we, followers of Jesus Christ, are all to make disciples, we must pour our lives into others. A Divine genius exists in reading the world through making disciples. For example, let's pretend we have one of the most effective evangelists of all time who could win 1,000 people a day to Christ. The evangelist could win 365,000 people to Christ in a years time. That is pretty impressive!
Now Let' stake one disciple, who though the aid of the Holy Spirit, wins one person to Christ. He then spends one year of their life pour into the new disciple with the expectation that they both will do the same with someone new next year. This would mean that the disciples would double who they reach each year. The disciples starts out with just one in year one, then two becomes four and year three four becomes eight. The disciples is exponential growth!
Here is what the numbers would look like for one man reaching 1,000 people a day verses one disciple reaching another disciple each year. It would take about 25 years for the discipler to catch up with the evangelist, but something interesting happens in year 26, the disciples have outpaced the evangelist by 7,562,216 people reached. The disciples keep doubling there number each year until they reach the world population of around 7.5 billion people in just 34 years! Discipleship will always outpace one person or a few people doing the evangelism in the long run.
Note: All conversion is contingent upon the Holy Spirit's involvement, we are messengers only!