The Gemara in Berachos (59a) discusses the ברכה one recites when seeing a rainbow. The first opinion says the brocha is זוכר הברית. The second opinion says the brocha is נאמן בבריתו וקיים במאמרו. רב פפא concludes that one should say both ברוך זוכר הברית ונאמן בבריתו וקיים במאמרו. Tosfos has a different גירסא and says the brocha is ברוך אתה ה’ אלקינו מלך העולם נאמן בבריתו וקיים בשבועתו וזוכר הברית. Tosfos also says that even though the brocha has many words it is still not a ברכה אריכתא and does not end off with ברוך. The מחבר (סימן רכ”ט סעיף א’) says the brocha is זוכר הברית נאמן בבריתו וקיים במאמרו. The Mishna Berurah says the גירסא of the Rambam and Tur is ונאמן בבריתו.
The meaning of the brocha is זוכר הברית – who remembers the covenant; ונאמן בבריתו – who is trustworthy in his covenant; וקיים במאמרו – and fulfills his word. The אבודרהם explains that even if Hashem had merely made a statement to this effect and not established a covenant, He would have nevertheless taken the same course of action. Alternatively, the Maharasha explains וקיים במאמרו is a reference to the rainbow itself. Although its appearance signifies the covenant between Hashem and Noach, rainbows did not begin to exist from Noach’s time; rather they existed from the first week of creation (Pirkei Avos 5:6). Thus we praise Hashem that He is קיים במאמרו sustaining His utterance at creation, which called natural phenomena such as the rainbow into being. [There are many explanations in the meforshim how the rainbow is a covenant if it was already created during בית השמשות as the Mishna in Avos states.]
The ביאור הלכה is מסופק if one has to see the whole rainbow which is half a circle, or even part of it. The תשובות והנהגות paskens, that since ספק ברכות להקל, if one does not see the whole rainbow he should not make a brocha. The brocha does not have to be recited while standing. The ברכת הבית holds that brocha is only recited once that day unless the clouds dispersed and returned again. However the קצות השלחן holds that even if the clouds did not disperse one can make a brocha on a different rainbow.
The מחבר says that one should not stare at the rainbow. He should look at it only in order to make a brocha. The Gemara in חגיגה (טז.) says that if one stares at a rainbow his eyesight becomes weak.
The Mishna Berurah brings from the חיי אדם that one should not inform his friend that there is a rainbow. He is being מוציא דבה on the generation that they should really be destroyed by a מבול. It is only because of the ברית that Hashem is not doing so.
Prepared by R’ Avrohom Yehoshua Ziskind