According to David Instone-Brewer, the people often referred to in the Gospels as ‘sinners’ (as in ‘tax collectors and sinners’) were actually prostitutes:-

‘Prostitutes at that time were called “sinners” in polite company, just as they were called “fallen women” by the Victorians. Interestingly, the Gospels never record Jesus using a euphemism, so when he condemned the Pharisees he said: “Tax collectors and prostitutes will get to the Kingdom of heaven before you” (Matthew 21:31).’

They are mentioned so often in the same breath because the tax collectors, as the nouveau riche of the day, would often throw banquets in the Roman style – feasts that included ‘entertainment’ by prostitutes after the meal.  It was such meals that Jesus himself often attended (Mt 9:10–11; 11:19; 21:31–32).  Instone-Brewer surmises that the woman who broke her alabaster jar of ointment over Jesus’ feet (Mt 26:6f) may have met the Saviour at just such a meal.

Instone-Brewer continues:-

‘It is striking that the Old Testament doesn’t actually condemn ordinary prostitutes, though it utterly condemns cultic prostitutes who had sex with “worshippers” at temples of the old Canaanite gods (Deuteronomy 23:17; Jeremiah 2:20). Also, there is severe condemnation for those who make people into prostitutes (Leviticus 19:29) and criticism of those who use them (Genesis 38; Proverbs 23:27; 29:3). Prostitutes themselves, however, were not ostracized by society – they could own property and could even present legal cases before the highest court of the land (1 Kings 3:16–27).’

Whereas the book of Proverbs regards both adultery and prostitution as wrong, it comes down far harder on the first than on the second (Prov 7:5-21).  According to Prov 6:26, ‘a prostitute only wants a loaf of bread, but an adulteress hunts you for your precious soul’.

If the woman who was caught in adultery (Jn 8:11) was a prostitute, as is quite likely, then Jesus’ command to her to ‘stop sinning’ was no easy matter; she would be out of work, with little prospect of re-employment.

The genealogy of Jesus includes two prostitutes: Tamar and Rahab, (Mt 1:3, 5; Gen 38; Josh 6:25).

‘The early church contained former sex workers and their clients, as Paul points out to the Corinthians (1 Cor 6:9–11), but to how many churches today could Paul say, “And that is what some of you were”?…How many Christians work among the street walkers in their own church locality? Unlike Jesus, who accepted invitations to meals where prostitutes would be present, we tend to avoid any situations which might even appear salacious or compromising to our reputation.’

Instone-Brewer, David. Jesus Scandals, The. Lion Hudson. Kindle Edition.