In Jewish society in Old Testament times, the most vulnerable people were non-jews/aliens, widows and orphans. A major reason being because they had no legal rights, and therefore could not appeal to the law for justice to protect themselves, but instead depended on their neighbors for compassion in everyday affairs. Note that the reason offered for God’s people to have such compassion is because God has first had compassion on them (the word in the Hebrew text used for compassion here is the same root used to indicate God’s grace).
Not unrelated, when Jesus is asked what is most important in everyday living, He re-states the first two Commandments: love God and neighbor. The Greek language of the New Testament had three words for love: eros for romantic love, philos for a more rational attachment to the basic goodness of created things and agape an identification with and sharing in Divine love.
It is this latter form which Jesus calls us to enter into and make manifest in our own daily activity by focusing on living a life of grace rooted in His life of love. Union with Him is the key!