There is a great joy that comes from being silent. As the wise say, "Before one speaks, he rules over his words, but after one speaks, the words rule over him." He can't take his words back.
The mazal of Adar, the month of happiness, is דגים, fish. The Klausenberger Rebbe zt'l explains that this is because fish are silent, and being silent is a great joy.
This can be the translation, לאיש שמחה, it is joyous for a person, פיו במענה, when he afflicts his mouth, and he doesn't speak. His silence will save him from a lot of trouble.
Avraham served the malachim tongue with mustard. Why specifically this food? Rebbe Dovid of Tolna zt'l explains that the malachim sought to understand why human beings are so precious to Hashem. Avraham gave them the tongue with mustard, implying that sometimes the tongue is hot and wants to say something sharp, especially when someone insulted you, and you want to answer back. But Yidden know how to hold back and remain silent even then, and that’s why Hashem loves us so much.
By makas tzefardeia the frogs were moser nefesh by jumping into the Egyptian ovens to do Hashem’s will (to go into the breads baking in the ovens). They were rewarded for that, and they remained alive. They didn’t get burned or baked by the fire (see Baal HaTurim, Shemos, 8:1). By makas bechoros the dogs didn’t bark. They too were rewarded, and whenever one has a non-kosher piece of meat, a נבילה, there’s a mitzvah to give it to the dogs.
It seems that the frogs’ deeds were greater than the dogs’ because they were moser nefesh. Yet the dogs’ reward is for all generations, while the frogs were only awarded in that generation. Why? Rebbe Dovid of Tolna zt’l said that this indicates that remaining silent is even harder.
