The General Epistle of James, written by the brother of our Lord, provides ethical instruction for all Jewish people who have become Christians. It is clear and practical in its dealing with Christian behavior.

James 5

5:4 Behold, the hire of the labourers who have reaped down your fields, which is of you kept back by fraud, crieth: and the cries of them which have reaped are entered into the ears of the Lord of sabaoth.