Have you ever seen a mustard seed? If you have, you know it’s pretty tiny. When deciding how to describe the kingdom to us, Jesus purposely used the smallest known seed at the time.
Jesus says that none of our goodness is good enough to pass muster. Likewise, none of our badness is bad enough to propel us outside Jesus’ death for sin.
Jesus tells a Parable about a master calling workers into His vineyard. What is the point here? How is "begrudging God His generosity" a problem for all of us?