Robin,

Israel was peculiar.  They were chosen.  They had the burden of Torah, i.e. obedience.  Israel was a witness to God's Law and His choosing. Deliverance out of Egypt and bondage was their witness.  They were not supposed to return.

Jesus Christ is the King of Israel - a kingdom not of this world, but nonetheless a kingdom indivisible from this world and the Jewishness of the 'King of the Jews.'  All men are called to serve this King of Kings and Lord of Lords.  He has conquered sin and death, 'whosoever believes in Him shall never die'.

What exactly would Israel convert the gentiles into if they had a commission to proselytize?  As Jesus said: "ye compass sea and land to make one proselyte, and when he is made, ye make him twofold more the child of hell than yourselves."

Obedience is hard.