2 John 1:1; 2 John 1:5; 2 John 1:8

1 The elder to the chosen lady and her children, whom I love in truth; and not only I, but also all who know the truth,
5 Now I ask you, lady, not as though I were writing to you a new commandment, but the one which we have had from the beginning, that we love one another.
8 Watch yourselves, that you do not lose what we have accomplished, but that you may receive a full reward.