The Criterion
۞ وَهُوَ ٱلَّذِى مَرَجَ ٱلْبَحْرَيْنِ هَـٰذَا عَذْبٌۭ فُرَاتٌۭ وَهَـٰذَا مِلْحٌ أُجَاجٌۭ وَجَعَلَ بَيْنَهُمَا بَرْزَخًۭا وَحِجْرًۭا مَّحْجُورًۭا
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.
Nearby ayahs help place verse 25:53 in sequence and meaning.
وَلَوْ شِئْنَا لَبَعَثْنَا فِى كُلِّ قَرْيَةٍۢ نَّذِيرًۭا
And if We had willed, We could have sent into every city a warner.
فَلَا تُطِعِ ٱلْكَـٰفِرِينَ وَجَـٰهِدْهُم بِهِۦ جِهَادًۭا كَبِيرًۭا
So do not obey the disbelievers, and strive against them with the Qur'an a great striving.
وَهُوَ ٱلَّذِى خَلَقَ مِنَ ٱلْمَآءِ بَشَرًۭا فَجَعَلَهُۥ نَسَبًۭا وَصِهْرًۭا ۗ وَكَانَ رَبُّكَ قَدِيرًۭا
And it is He who has created from water a human being and made him [a relative by] lineage and marriage. And ever is your Lord competent [concerning creation].
وَيَعْبُدُونَ مِن دُونِ ٱللَّهِ مَا لَا يَنفَعُهُمْ وَلَا يَضُرُّهُمْ ۗ وَكَانَ ٱلْكَافِرُ عَلَىٰ رَبِّهِۦ ظَهِيرًۭا
But they worship rather than Allah that which does not benefit them or harm them, and the disbeliever is ever, against his Lord, an assistant [to Satan].