Deuteronomy 4:2
2 You shall not add to the word which I command you, nor take from it, that you may keep the commandments of the Lord your God which I command you.
John 13:34-35
34 A new commandment I give to you, that you love one another; as I have loved you, that you also love one another. 35 By this all will know that you are My disciples, if you have love for one another.”
Jesus expanded on many of the commands and that they start from your heart whether it was murder can start from hate or adultery can start from lust. He summed up the commands into 2, but a sum doesnt not equal a cancellation of it.
Matthew 22:37-40
37 Jesus said to him, “‘You shall love the Lord your God with all your heart, with all your soul, and with all your mind.’ 38 This is the first and great commandment. 39 And the second is like it: ‘You shall love your neighbor as yourself.’ 40 On these two commandments hang all the Law and the Prophets.”
These 2 commands came from:
Leviticus 19:18
18 You shall not take vengeance, nor bear any grudge against the children of your people, but you shall love your neighbor as yourself: I am the Lord.
Deuteronomy 6:5
5 You shall love the Lord your God with all your heart, with all your soul, and with all your strength.
So back to Deut 4:2, Jesus could not add any New Commands to the word of God, so the excuses used on here by some that the only thing they have to follow is the one NEW command in John 13:34-35, and disregard everything else is FALSE.
Jesus was not giving his disciples a new command, he was just giving them a lesson on a original command for the first time and showing them the example on how he lived it out for them.