What is the difference between "Then cast him into the river" and "So We cast them into the sea"?

The meanings of "nabdh" (casting away) and "ilqa'" (throwing) are the same according to linguists. "Nabd" is to throw something from the hand, whether in front or behind, and it is used for casting off and removing something. They specifically associate "nabdh" with throwing away something worn-out and despised, as in the Almighty's saying: "So We cast them into the sea" [فَنَبَذْناهُمْ فِي الْيَمِّ]; because they were thrown with disdain, as if they were something worn-out and insignificant, unlike the throwing of Moses' mother her child into the sea. "Nabd" expresses contempt for something and throwing it away due to its lack of importance.