Five times altogether, according to the New King James version:
Jan 31 2010, 9:45 PM
John 13:34 "A new commandment I give to you, that you love one another; as I have loved you, that you also love one another.
John 13:35 "By this all will know that you are My disciples, if you have love for one another."
John 15:12 "This is My commandment, that you love one another as I have loved you.
John 15:17 "These things I command you, that you love one another.