The greatest commandments are only of 2 found in the New Testament in which I was taught by Pastor Apollo Quiboloy.
30 "And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment."
31 "And the second is like, namely this, Thou shalt love thy neighbour as thyself. There is none other commandment greater than these."
If we were to just apply these two commandments we would honor our love for our one and only Almighty Father, our Lord Jesus Christ the Creator of all, and if you happen to love your neighbor as yourself there would not be any war or hate happening in the world today. Applying these 2 commandments, umbrella the commandments and laws in the Old Testament.
And how do we love our neighbors? (Matthew 5:43-44)
43 "Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy."
44 "But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you and persecute you."