Why is Elijah mentioned in the blessings of the haftorah and in grace after meals?

Question

In the blessings of the haftorah, Elijah is mentioned and in grace after meals he is also mentioned. Why?

Answer 1

I don't believe there is an answer specific to your question, other than to say Elijah is beloved because he is the harbinger of the Messiah, and so is frequently invoked in our tradition to perform many tasks:

-During Havdalah, at the conclusion of Shabbat, we sing the song Eliahu HaNavi, asking Elijah to come and bring the Messiah with him:

Eliahu hanavi... Bimhera veyamenu yavo elenu, ‘im Mashiach ben David. -- Elijah the Prophet… May he come to us soon, in our day, with the Messiah, the son of David.

-In the Birkat HaMazon, the Grace after Meals, we also ask for Elijah:

הָרַחֲמָן, הוּא יִשְׁלַח לָֽנוּ אֶת אֵלִיָּֽהוּ הַנָּבִיא זָכוּר לַטּוֹב, וִיבַשֶּׂר לָֽנוּ בְּשׂוֹרוֹת טוֹבוֹת יְשׁוּעוֹת וְנֶחָמוֹת -- May the All-Merciful One send us Elijah the Prophet, may he be remembered for good, and may he announce to us news of goodness, salvation, and comfort.

-On Pessah, Ashkenazic Jews reserve a seat and a cup of wine for Elijah, and even open the door of the house for him, hoping he will show up.

-Elijah “attends” all circumcisions. Here is why. When Elijah was hiding in a cave, God visited him and asked him “Why are you here, Elijah?” [1Kings 19:9] He replied: I am moved by zeal for the Lord, the God of Hosts, for the Israelites have forsaken Your covenant [brit], torn down Your altars, and put Your prophets to the sword. I alone am left, and they are out to take my life. [1Kings 19:10, 14] God resented Elijah for badmouthing Israel. The Zohar says: God said to [Elijah:]… The mouth that accused Israel of forsaking the covenant shall testify that they are observing it. [Zohar 1:93a]

So the rabbis decreed that Elijah would be present at every circumcision to satisfy himself that the Jews indeed fulfill that commandment. The Midrash says:

Hence the sages instituted (the custom) that people should have a seat of honor for [Elijah at every circumcision]; for Elijah, may he be remembered for good, is called the Messenger of the Covenant, as it is said [in Malachi]: The messenger of the covenant [brit], that you desire, is coming. [Mal. 3:1] [Pirkei D’Rabbi Eliezer 29].

-Elijah is said to reappear frequently, sometimes in disguise, to help people in distress and make peace between individuals. Talmud offers many tales of his reappearances. [E.g., B. B. 59b, Shab. 33b, B. M. 83b–84a, Sanh. 98a] One time, the Romans were pursuing Rabbi Meir. Elijah came disguised as a prostitute and embraced Rabbi Meir. The Romans saw this and concluded, “This cannot be Rabbi Meir. He would never act that way.” [Av. Zar. 18b]

-Elijah will settle every outstanding dispute on Jewish law. [E.g., Ber. 35b, Ed. 8:7, Men. 45a, Bek. 24a] In the Talmud, unresolved difficulties are frequently followed by the word Teku (תיקוּ), “let it stand,” which is said to be an acronym for Tishbi yetareẓ kushyot u-ve’ayot -- “the Tishbite [Elijah] will resolve difficulties and problems.”

My list is not exhaustive.