Matthew 28:19-20
¹⁹Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: ²⁰Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen.

This was Jesus last command and promise to His disciples before He ascended into Heaven. Jesus goal was to reach all nations, yet He never visited most of the nations in His time. One man physically cannot preach the Gospel to all nations by himself. Jesus was God in the flesh, and He didn't even try. Jesus didn't even try to convert all of Israel by Himself. Jesus spent the vast majority of His life focusing on 12 men. Jesus taught and equipped these men to teach and equip other men. Jesus' goal was to use multiplication to reach the all nations. If each of the 11 faithful disciples taught and equipped 11 others, in just 9 generations, all people and all nations would be reached. We can use the same strategy today. Don't try to convert everyone; focus on a few. Teach and equip them to teach and equip others.