'Command' in the Bible

he who is saying, 'I have known him,' and his command is not keeping, a liar he is, and in him the truth is not;

Brethren, a new command I write not to you, but an old command, that ye had from the beginning -- the old command is the word that ye heard from the beginning;

again, a new command I write to you, which thing is true in him and in you, because the darkness doth pass away, and the true light doth now shine;

and this is His command, that we may believe in the name of His Son Jesus Christ, and may love one another, even as He did give command to us,

and this is the command we have from Him, that he who is loving God, may also love his brother.