When Moses led the Hebrews to Mount Sinai, he explained that God wanted to sign a blood pact or covenant with them.  He then climbed the mountain to receive the terms–the 10 commandments.  A month passed with no word from the prophet.  The Hebrews grew restless and eventually abandoned their God.  They demanded that Moses' brother Aaron create a statue of Hathor, the Egyptian goddess of fertility.  She was often pictured as a calf. 
The key scene in this story is that of Moses pleading to God for the forgiveness of the people.  The Psalms picture him as standing in a breach between two rocks–sort of straddling both heaven and earth. 

Today's Gospel begins with a stinging criticism of Jesus: he eats with sinners!  Tax collectors were little more legalized thieves in 1st century Palestine.  Worse yet, they were traitors who collaborated with the occupying government. " Good people" didn't associate with them, much less break bread with the unsavory lot.  They were literally excommunicated from "polite" society. 
Jesus counters this self-righteousness with three parables.  They illustrate the joy brought by conversion.