The first mention of the term 'Raychaudhuri Equation' appeared in a research paper published in 1965 by George F.R. Ellis and Stephen Hawking. The Raychaudhuri equation hit the zenith of fame as it was a key tool in the hands of young relativists like Stephen Hawking and Roger Penrose in the middle of the late 1960s in their attempt to answer the question on the existence of space-time singularities and to explain the theory of universe. In fact, this equation is important as a fundamental lemma for the Penrose-Hawking singularity theorems.