But the Pharisees and the teachers of the law muttered, “This man welcomes sinners and eats with them.” – Luke 15:2

This insult is what prompts Jesus to tell three stories about the joy of finding something that was lost. The final story is about a person who was lost and then found (the younger, so-called “prodigal” son), but it adds the twist of the older son refusing to come to the party.

Jesus is clearly casting the Pharisees and teachers of the law in the role of the older brother, trying to help them see that, ironically, in their exclusion of “sinners” from the company of the blessed, they are in fact excluding themselves from the blessing God is pouring out!
The invitation is to let go of the status hierarchy they’ve created, to embrace the fact that it isn’t real. That we are all “sinners,” really, all in need of grace, all in need of mercy, all in need of forgiveness.
Once you realize the status hierarchy isn’t real, what was meant to be an insult (“This man welcomes sinners and eats with them”) turns into very good news indeed!
Who is the painter of the painting featured here?
I believe it is Australian-born painter Louis Kahan, painted in 1949. More info at the bottom of this page: http://iconsandimagery.blogspot.com/2010/11/wedding-at-cana.html