Does gratiano use the analogy of a ship and a prodigal son to prove his point

Gratiano then talks about a merchant ship ("bark") looks good with flags adorning it ("scarfed") and looks most nobly when it embarks than when, like the prodigal son, it returns to port looking lean and withered like a beggar. Of course this is an allusion to the Old Testament story of the Prodigal Son retuning to his father poor and humble.