NET
23 Now this is his commandment: that we believe in the name of his Son Jesus Christ and love one another, just as he gave us the commandment.
Darby
23 And this is his commandment, that we believe on the name of his Son Jesus Christ, and that we love one another, even as he has given us commandment.
KJV
23 And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment.