This woman perceived and appreciated a greatness in Jesus that motivated her to so abase herself as to weep, cleanse His feet with her tears, kiss, and anoint them! Notice her emotion, courage, devotion (oblivious of public opinion), and humility (in performing the task of a slave). We can safely guess that Jesus had turned this woman from a life of sin. She may have been among the crowds who were convicted by His messages. When she heard He was nearby, she rushed to Simon's home, ignoring the scorn of others to express her gratitude to the One who had set her aright.
Her deed expressed her love and gratitude, springing from her recognition of or faith in His greatness as contrasted to her unworthiness. She felt obligated to respond in a way so memorable that God recorded it for all humanity for all time to witness. Note that the Bible shows human lips touching Jesus only twice: here and Judas' kiss of betrayal.
In contrast, Simon the Pharisee, evidently a man of some substance and ambition, was moved to invite the popular Jesus to his home. Self-concerned and inhospitable, he did not offer Jesus even the customary services a host normally provided visitors to his home.
From the context we can assume that he felt himself to be at least Jesus' equal. His conclusion that Jesus was no prophet probably suggests he felt superior to Him, that He was no more than an interesting celebrity. This biased self-evaluation in relation to Jesus produced in him no sense of obligation and thus no corresponding gratitude, humility, or act of love—let alone common courtesies.
Had he a heart at all? The scene unfolding at his respectable table scandalized him, but God thought it so inspiring, He recorded it for our benefit. Simon judged, "She is a sinner." "No, Simon," Jesus replied, "she was a sinner." In this lies a major clue to the difference between the two people.
Simon and the woman had something in common, according to the parable: Both were debtors to the same creditor, and neither could meet His obligation.
John W. Ritenbaugh
Passover, Obligation, and Love