From the little bit we know about the lives of Simon and Jude we can find an example of what it means to love one another. They stuck it out, even when times got tough. They might have hesitated a bit on Good Friday, perhaps even like the others they ran away.
But Simon and Jude went on to be faithful witnesses of the saving power of Jesus. This was due to the support and love they received from their fellow Apostles, the wider community of disciples. And, if we believe that they travelled together for 30 years, the love they most certainly had for one another.