The Torah then tells us that Moshe’s sister, Miriam, remains standing at the Nile to see what would happen to Moshe. The Gemara states that she was rewarded for this act many years later when she was punished with tsoraas for speaking lashon hara about Moshe.  She was quarantined for seven days, but HaShem instructed the people to stop travelling and wait the seven days for her.  This was a measure for measure reward for the fact that she waited to see what would happen to Moshe. The obvious question is why was the fact that she waited for Moshe such a praiseworthy action so much so the entire nation waited for her for seven days in the desert? It seems that her maintaining hope was the key to her future reward. Whatever the situation, as long as one keeps his hope alive, there remains a potential cure, or a potential redemption, or a potential salvation to the crises. One must maintain hope in order to have a chance to see that salvation come to fruition. Had Miriam given up hope, then the last connection to the future deliverance of the Jewish people would have been severed. This is why her act of faith was so crucial”. Credits - Rabbi Y. Gefen for bringing down the idea