Qur'an 25:53

۞ وَهُوَ ٱلَّذِى مَرَجَ ٱلْبَحْرَيْنِ هَـٰذَا عَذْبٌ فُرَاتٌ وَهَـٰذَا مِلْحٌ أُجَاجٌ وَجَعَلَ بَيْنَهُمَا بَرْزَخًا وَحِجْرًا مَّحْجُورًا

“And it is He who has released [simultaneously] the two seas [i.e., bodies of water], one fresh and sweet and one salty and bitter, and He placed between them a barrier and prohibiting partition.”

Al-Furqaan 25:53 · Saheeh International