وَاتْرُ‌كِ الْبَحْرَ‌ رَ‌هْوًا "And leave the sea in the state of stillness; (44:24) " The word rahwan means 'to be still/calm/motionless'. When Prophet Musa (علیہ السلام) and his companions crossed the sea, Musa ill naturally desired for the sea to go back to its original state. So he wanted to strike it with his staff so that it would form a barrier between them and Fir'aun to prevent him from reaching them. But Allah commanded him to leave it as it was, quiet and divided, and gave him the glad tidings that they were a host to be drowned, and he should not fear either being overtaken by Fir'aun or drowning in the sea. When Fir'aun, with his host, will reach the middle of the dry path, Allah will cause the water to flow and they will drown. (Ibn Kathir).