And it is He who has released [simultaneously] the two seas, one fresh
and sweet and one salty and bitter, and He placed between them a barrier
and prohibiting partition. ( Quran, Surat Furqan, 53)
This
invisible barrier is because of the difference between the consistency
of salty and sweet water. In other words, the salty and sweet water‘s
different densities make them not to mix together for a long time.
How
does the very God who does not let the neighboring salty and fresh seas
be mixed together allow to the right and wrong and disbelief and faith
be mixed together?!
Imam Sadiq (P.B.U.H.): Ali and Fatima (P.B.U.T)
are those very deep seas that none of them is superior to the other.
There is a joint between them who is Muhammad, the Prophet of Allah
(P.B.U.H.) and the fruits of these two seas are pearl and coral who are
Hassan and Hussain (P.B.U.T).
_ And He showeth you His tokens. Which, then, of the tokens of Allah do ye deny? (Quran, Surat Ghafir, 81)