Conversation so far:
what is the lesson in the parable of the workers in the vineyard
The parable of the workers in the vineyard stresses God's unmerited grace, rather than any sense of earning God's favour.
who wrote the parable of the workers in the vineyard
The Parable of the Workers in the Vineyard is a parable of Jesus.

Question: where does the parable appear
Self-contained rewrite: where does the parable of the workers in the vineyard appear