While Jesus gave many important teachings, his last commandment is often referred to as
the New Commandment or
the Great Commandment.
It's found in John 13:34-35:
"A new command I give you: Love one another. As I have loved you, so you must love one another. By this everyone will know that you are my disciples, if you love one another."
So, while not officially named as such, it is commonly known as the "New Commandment."