The knowledge of Fiqh (Islamic jurisprudence) is not a new thing. On the contrary, it is essence of the Holy Quran and Hadith and it is the name given to the understanding of religion. It is necessary for every Muslim. Almighty Allah says:
Translation: That they may acquire deeper knowledge (i.e. thorough understanding and insight) of Din (Religion). Surah Tauba (09: 122)
Allah grants the knowledge of Fiqh to only those servants for whom He wishes well. As there is Hadith of Sahih Bukhari:
Translation: The Holy Prophet (Sallallahu alaihi wa sallam) said: The person whom Allah wishes well is granted understanding of religion and there is nothing contrary to the fact that I am the one who disburses and Allah is the One who grants. (Sahih Bukhari, Hadith No: 71)