Performed by the American Hasidic Jewish singer and songwriter Mordechai Ben David, this song is often sung on Lag B’Omer because of the association between the holiday and the great sage, Rabbi Akiva. Lag B’Omer marks the end of the plague that killed 24,000 of his students, as well as passing of his greatest disciple, Rabbi Shimon Bar Yochai, the alleged author of the Kabbalistic book of the Zohar. The lyrics are a quote from Rabbi Akiva from the last Mishnah in Tractate Yoma:
Rabbi Akiva said: You should be happy, Oh Israel. In front of whom do you purify yourselves and who purifies you? Your father in heaven.
As it says, «I will toss pure waters on all of you and you will be purified.» (Ezekiel 36:25)
And it says: «HaShem is the hope of Israel.» (Jeremiah 17:13)
Like a mikvah purifies the impure, the Holy One Blessed Be He purifies Israel.