[Regarding His saying,] "It is your Lord who drives the ship for you," meaning: He makes it sail, "in the sea so that you may seek of His bounty," meaning: the seeking of trade upon the sea. "Indeed, He is ever, to you, Merciful." By His kindness and mercy, He subjected that for you, and mercy for the disbeliever in this context is the mercy of the worldly life.
﴿رَبُّكُمُ الَّذِي يُزْجِي لَكُمُ الْفُلْكَ﴾ أَيْ: يُجْرِيهَا ﴿فِي الْبَحْرِ لِتَبْتَغُوا من فَضله﴾ يَعْنِي: طَلَبَ التِّجَارَةِ فِي الْبَحْرِ ﴿إِنَّه كَانَ بكم رحِيما﴾ فَبِرَأْفَتِهِ وَرَحْمَتِهِ سَخَّرَ لَكُمْ ذَلِكَ، وَالرَّحْمَةُ لِلْكَافِرِ فِي هَذَا رَحْمَةُ الدُّنْيَا.