I believe the proof of multiplication is found in the fourth generation. 2 Timothy 2:2 is the key verse about multiplying disciples in the New Testament.
And the things you [Timothy] have heard me [Paul] say in the presence of many witnesses entrust to reliable people [third generation] who will also be qualified to teach others [fourth generation and beyond]. (2 Tim. 2:2 NIV)
In this verse we see four generations of reproduction: Paul, Timothy, reliable people and others also. “Others also” represent more than just a fourth generation—that phrase includes every generation thereafter. Once we pass the fourth generation, the momentum kicks in and succeeding generations don’t just become possible, but probable.
A strong leader will attract other leaders, who, because they are leaders, will have followers. In that sense, we can have three generations via addition. But to see the fourth generation, we must be doing things differently—we must be giving it all away to get through the barrier between addition and multiplication. We should hold this marker up as our scorecard of success more than the numbers that are in attendance. Once we break through the Gen-4 barrier, multiplication has a momentum of its own. It is also beyond anyone’s control.
Movements happen because many leaders in that movement are developing streams of multiplication beyond the fourth generation. This can only happen as the DNA of movements is clearly and intentionally passed and implemented from one generation to the next. The best measurement of movements, then, is the number of streams whose leaders have overcome that fourth-generation barrier.