The “Law of God is divided into two parts”: “One is the fundamental basis which comprises all spiritual things,” and the other “refers to material things”. The first part “does not change nor alter” with time, whereas those pertaining to “material world” are “modified and altered in each prophetic cycle in accordance with the necessities of the times.”

… the Law of God is divided into two parts. One is the fundamental basis which comprises all spiritual things -- that is to say, it refers to the spiritual virtues and divine qualities; this does not change nor alter: it is the Holy of Holies, which is the essence of the Law of Adam, Noah, Abraham, Moses, Christ, Muhammad, the Báb, and Bahá'u'lláh, and which lasts and is established in all the prophetic cycles. It will never be abrogated, for it is spiritual and not material truth; it is faith, knowledge, certitude, justice, piety, righteousness, trustworthiness, love of God, benevolence, purity, detachment, humility, meekness, patience and constancy. It shows mercy to the poor, defends the oppressed, gives to the wretched and uplifts the fallen. 

These divine qualities, these eternal commandments, will never be abolished; nay, they will last and remain established for ever and ever. These virtues of humanity will be renewed in each of the different cycles; for at the end of every cycle the spiritual Law of God -- that is to say, the human virtues -- disappears, and only the form subsists….. 

The second part of the Religion of God, which refers to the material world, and which comprises fasting, prayer, forms of worship, marriage and divorce, the abolition of slavery, legal processes, transactions, indemnities for murder, violence, theft and injuries -- this part of the Law of God, which refers to material things, is modified and altered in each prophetic cycle in accordance with the necessities of the times. (‘Abdu'l-Baha, Some Answered Questions)

It is through our “deeds” that the “brightness” of our “light can be shed upon the whole earth.”

Strive that ye may be enabled to manifest to the peoples of the earth the signs of God, and to mirror forth His commandments. Let your acts be a guide unto all mankind, for the professions of most men, be they high or low, differ from their conduct. It is through your deeds that ye can distinguish yourselves from others. Through them the brightness of your light can be shed upon the whole earth. Happy is the man that heedeth My counsel, and keepeth the precepts prescribed by Him Who is the All-Knowing, the All-Wise. (Baha'u'llah, ‘Gleanings from the Writings of Baha'u'llah’; The Baha’i World 2002-2003)

The “virtues” that “befit” one’s “dignity are forbearance, mercy, compassion and loving-kindness towards all the peoples and kindreds of the earth.”

All men have been created to carry forward an ever-advancing civilization. The Almighty beareth Me witness: To act like the beasts of the field is unworthy of man. Those virtues that befit his dignity are forbearance, mercy, compassion and loving-kindness towards all the peoples and kindreds of the earth. (Baha'u'llah, ‘Gleanings from the Writings of Baha'u'llah’)