Lactantius: True religion

"IT is plain that no other hope of life is set before man, except that, laying aside vanities and wretched error, he should know God, and serve God; except he renounce this temporary life, and train himself by the principles of righteousness for the cultivation of true religion. For we are created on this condition, that we pay just and due obedience to God who created us, that we should know and follow Him alone. We are "bound" and "tied" to God by this "chain of piety"; from which "religion" itself received its name."

~Lactantius (c. 250 – c. 325): The Divine Institutes, IV, 28.

The beginning of Lactantius’ Divinae institutiones in a Renaissance

manuscript written in Florence ca. 1420–1430 by Guglielmino Tanaglia.