When the astrologers warned phaoroh that a boy would be born to the Israelites who would annhilate his empire, he ordered to slay every newly born Israelite boy. Subsequently thousands of infants were slain. At the critical time Musa was born nd his mother was inspired tht she might suckle him without any fear nd at a proper time should place the baby in an ark and leave it in the river. Allah inspired to her that her son would be brought back to her at the specified time. She acted to the will of Allah and Allah kept all his prmises.
Look! She had trusted in Allah and was rewarded graciously for that.