In the custom of gleaning, some remnants are left over for the alien, fatherless, and the widow, but the remnants were not picked and handed to them, they had to go get them for themselves.

It was through this custom that Boaz was introduced to Ruth…and we know where that led. Ruth 4:13
So Boaz took Ruth and she became his wife. Then he went to her, and the LORD enabled her to conceive, and she gave birth to a son.
Ruth 4:17b
And they named him Obed. He was the father of Jesse, the father of David. (ancestor of Jesus)

Again God warns the Israelites about the nations teaching them to follow their detestable ways.
Deut 23:14
For the LORD your God moves about in your camp to protect you and to deliver your enemies to you. Your camp must be holy, so that he will not see among you anything indecent and turn away from you.

What does it mean for us today to be holy?