Our Lord commanded no one to go out and "convert" the world.  We are told to evangelize, that is, to preach the gospel into all the world. (Matthew 16:15)  However, this preaching of the gospel does not mean conversion

Presently, Satan is blinding mankind. 2 Corinthians 4:4, “the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.” The world will not be converted until Christ reigns on earth. 

First, our Lord, Jesus Christ, returns as King. Revelation 19:11-15, “And I saw heaven opened, and behold a white horse; and he that sat upon him was called Faithful and True, and in righteousness he doth judge and make war. His eyes were as a flame of fire, and on his head were many crowns…his name is called The Word of God. And the armies which were in heaven followed him…out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron,” Revelation 19:11-15. 

Christ’s iron rule will halt all war and establish righteousness. Israel will be converted first (Zechariah 12:10-14) and then the rest of the world will flow to Israel to be educated and converted. Jeremiah 31:33,34, “After those days (Armageddon), saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. And they shall teach no more every man his neighbor, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more.” (See also Isaiah 2:2-4.)