Verse 50 refers to certain things which had happened in the days of Sayyidna Musa (علیہ السلام) (Moses). He, in his capacity as a messenger of Allah, continued efforts for a long time to make the Pharaoh and his people see Truth, but when they persisted in their denial, Allah commanded him to take the Israelites along with him and leave Egypt surreptitiously. On their way, they came across a sea while the Pharaoh was behind him with his army in hot pursuit. Allah commanded the sea to split, and make way for Sayyidna Musa (علیہ السلام) and his people. So, they went over smoothly. But when the Pharaoh and his army followed them into the sea, it gathered the water back so that the Pharaoh and his men were drowned then and there.
A doctrinal point
Verse 50 speaks of the splitting of the sea, and clearly proves that miracles do occur at the hands of prophets, which some Westernized Muslims have been trying to deny. (Bayn al-Quran (