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. That which we had from the beginning - The commandment to love one another was what they had heard from the first publication of Christianity, and what he wishes this excellent woman to inculcate on all those under her care. The mode of address here shows that it was a person, not a Church, to which the apostle wrote.
Related Commentaries of 2 John 1:5
2 John 1:5
5 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.