Mentioning Krias Yam Suf
Besides the mitzvah of mentioning Yetzias Mitzrayim, the Exodus from Egypt both by day and by night, there is a mitzvah of mentioning Kriyas Yam Suf, the splitting of the Red Sea. We do so twice every morning during Shacharis, in Shiras Hayam, Az Yashir, and in the brachah of Emes Veyatziv, as well as once in the evening, in the brachah of Emes V’Emunah. The custom is to say the Shira standing up. It says in poskim (Mishnah Berurah 51:17) that one should say it be’simchah, with joy and with song, and if they do so, feeling as if they are actually crossing the yam, Hashem forgives all their aveiros, sins.