I actually think that commandment falls within the two greatest commandments I mentioned previously. And by the way, Jesus said that the two I listed (love God with all your mind, etc and love others as yourself were the greatest....period.:
Mar 12:31 And the second [is] like, [namely] this, Thou shalt love thy neighbour as thyself. There is none other commandment greater than these.
At that time, that was true. And Jesus was talking to those under the law. But later, He gave a new commandment. Why, because the earlier two didn't cut it. They didn't result in salvation.