On Jewish Hospitality
For the Pharisee to invite Jesus to a meal at his house (Luke 7:36) was not unusual. Jewish tradition held that welcoming strangers to ones home was akin to welcoming the presence of the Lord himself. After all, was that not how Abraham received the blessing of the Lord, by entertaining three strangers (Genesis 18)? It would be especially prestigious to have a well-known scholar at your table, even one as controversial as this Nazarene. Such a gesture would absolve a man of his obligation to make the daily sacrifice, according to tradition.
This Pharisee didn’t seem to want to offer Jesus too much honor, though, did he? He neglected to offer water to wash his feet. He neglected to greet him with a kiss, or to anoint him with olive oil. We can’t know for sure what was going through Simon’s head as he prepared for his guest, but we can guess.
As far as Simon was concerned, Jesus was no teacher, but a heretic, just like that rabble-rouser John (and he had heard a rumor that he wasn’t likely to be around much longer, either; if he hadn’t already lost his head by then). These protocol breaches were subtle hints that he was onto Jesus. “I know you’re a fraud. Pretty soon everyone will.”
The appearance of the woman was a surprise, but not entirely out of the ordinary, since stragglers often came around in hopes that there might be scraps leftover for them. When she began to weep, and actually touched Jesus, Simon had to think that the moment of come-uppance was at hand. Little did he suspect that he was going to be the one exposed, and not Jesus!
—Rick Rossing
Here are some helpful resources:
https://www.myjewishlearning.com/article/jewish-hospitality/
https://www.jewishvirtuallibrary.org/hospitality-in-judaism
https://www.jewishencyclopedia.com/articles/7905-hospitality