As we know, for running the administration of any department o0r institution in this world, certain laws and rules are required to be framed for its smooth and efficient
day-to-day working. As for example, the Railway Department has got its own strict laws and rules, Aviation Department, Revenue Department, Income Tax Department, Judicial Department, Public Works Department and all other such Departments have their own rules and regulations for their smooth and efficient administration. Even a small Village Panchayat, Taluka Panchayat or District Panchayat or a Municipal Corporation or a big State or a Country Government - each one of them has got its own separate laws and rules under which it is governed.

In the same way, there must be some law which governs the administration of this whole, vast, infinite universe.

The rising and setting of the sun in the east and the west punctually and strictly according to the time shown in Astrology, the harmonious movement of the earth, sun, moon, stars, planets etc. around each other on their pre-destined orbits and destined routes as shown in Asttonomy, the Inception, Maintenance and Dissolution of all the animate bodies and inanimate objects and things in the whole universe, the coming of winter, summer and monsoon seasons, the ripening of fruits, flowers, grass and shrubs on the earth, the proper existence of mountains, rivers, oceans etc., the working of the principles of specific gravity and relative density of objects and things
on the earth, the evaporation of water from the sea to the sky, the formation of the clouds and their showering on the earth, the mysterious running of the cycle of birth and death etc. for the smooth and effective administration and execution of all these environments, there must be some strict law under which the whole infinite universe is governed.This law is known as the 'Law of Karma' as stated by Goswami Tulsidasji in his Ramayana as under:

KARMA PRADHAN VISHVA RACHI RAKHA,
JO JAS KARAI SO TAS FAL CHAKHA.

The whole universe is governed by the 'Law of Karma' and the most important section and the fundamental principle of this law is -

JO JAS KARAI SO TAS FAL CHAKHA.

As you sow, so shall you reap.

Thus the 'Law of Karma' is the law of
(1) action and reaction
(2) cause and effect
(3) effort and destiny.

Action and reaction, cause and effect, effort and destiny
are all equal and opposite.