What is God-given is what we call human nature. To fulfil the law of our human nature is what we call the moral law. The cultivation of the moral law… - Zisi

To arrive at understanding from being one's true self is called nature, and to arrive at being one's true self from understanding is called culture. He who is his true self has thereby understanding, and he who has understanding finds thereby his true self.
Only those who are their absolute true selves in the world can fulfil their own nature; only those who fulfil their own nature can fulfil the nature of others; only those who fulfil the nature of others can fulfil the nature of things; those who fulfil the nature of things are worthy to help Mother Nature in growing and sustaining life; and those who are worthy to help Mother Nature in growing and sustaining life are the equals of heaven and earth.

Nature is vast, deep, high, intelligent, infinite and eternal. The heaven appearing before us is only this bright, shining mass; but in its immeasurable extent, the sun, the moon, stars and constellations are suspended in it, and all things are embraced under it. The earth, appearing before us, is but a handful of soil; but in all its breadth and depth, it sustains mighty mountains without feeling their weight; rivers and seas dash against it without causing it to leak. The mountain appearing before us is only a mass of rock; but in all the vastness of its size, grass and vegetation grow upon it, birds and beasts dwell on it, and treasures of precious minerals are found in it. The water appearing before us is but a ladleful of liquid; but in all its unfathomable depths, the largest crustaceans, dragons, fishes, and turtles are produced in them, and all useful products abound in them.
In the Book of Songs it is said: "The ordinance of God, / How inscrutable it is and goes on for ever." That is to say, this is the essence of God.

Truth means the fulfilment of our self; and moral law means following the law of our being. Truth is the beginning and end (the substance) of material existence. Without truth there is no material existence. It is for this reason that the moral man values truth.
Truth is not only the fulfilment of our own being; it is that by which things outside of us have an existence. The fulfilment of our being is moral sense. The fulfilment of the nature of things outside of us is intellect. These, moral sense and intellect, are the powers or faculties of our being. They combine the inner or subjective and outer or objective use of the power of the mind. Therefore, with truth, everything done is right.