ISB ~ Galatians 3 v19

It was added:The Torah was inserted into history between the Abrahamic covenant and the New Covenant.

because of:The Greek can indicate either the goal (“for the sake of”) or the cause (“by reason of”) for adding the Law.

Paul may have both ideas in mind:the goal of the Law was to expose transgressions and heighten Israel’s awareness of sin (Rom 3:20; 5:20; 7:7); the cause for adding the Law, at least the bulk of its sacrificial and ceremonial rites, was the rebellion of Israel during the Exodus period, particularly the golden calf transgression (see, e.g., Christian theologians St. Justin Martyr, Dialogue with Trypho 18-22; St. Irenaeus, Against Heresies 4, 15; St. Aphrahat, Demonstrations 15, 8; St. Thomas Aquinas, Summa Theologiae I-II, 102, 3).

ordained by angels:Jewish tradition based on the Greek version of Deut 33:2 held that Moses received the Torah from the hands of the angels (Acts 7:53; Heb 2:2; Josephus, Antiquities 15, 136).