Numbers 15:38-39

³⁸Speak to the children of Israel, and bid those who they make them fringes in the borders of their garments throughout their generations, and that they put on the fringe of each border a cord of blue: ³⁹and it shall be to you for a fringe, that you may look on it, and remember all the commandments of Yahweh, and do them; and that you not follow after your own heart and your own eyes, after which you use to play the prostitute;