The duty of believing

From the book, Sanctification, or The Highway of Holiness, by Walter Marshall:

If we put the question, “What must we do, that we may work the works of God?” Christ resolveth it, “That we believe on Him whom He hath sent” (John 6: 28, 29). He putteth us first upon the work of believing which is the work of God by way of eminency, the work of works, because all other good works proceed from it.