'Commandment' in the Bible

I rejoiced greatly that I found of thy children walking in truth, as we have received a commandment from the Father.

And now I beseech thee, lady, not as though I wrote a new commandment unto thee, but that which we had from the beginning, that we love one another.

And this is love, that we walk after his commandments. This is the commandment, That, as ye have heard from the beginning, ye should walk in it.