Albert Barnes Commentary Matthew 23:37

"O Jerusalem, Jerusalem, that killeth the prophets, and stoneth them that are sent unto her! how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not!" — Matthew 23:37 (ASV)

O Jerusalem, etc. See Barnes on Luke 19:41-42.

Would have gathered. Would have protected and saved.

Your children. Your people.