The teaching of the Bnei Yissaskhar to pray for a beautiful etrog (citron) on Tu b’Shevat is fairly well-known (Bnei Yissaskhar, Shevat 2:2). I’m fairly confident that the link to the prayer the Ben Ish Chai composed for having a beautiful etrog is making the rounds of the ‘Net, even as we speak. I would like to add a bit, from a teaching of Rebbe Nachman.
In Sichot HaRan (Rabbi Nachman’s Wisdom) #87 the Rebbe says that in an ideal world, the beauty of one’’s etrog for the festival of Sukkot would match the beauty of one’s Days of Awe, the ten days from Rosh HaShanah through Yom Kippur (inclusive). In brief (and leaving out all of the Kabbalah), he explains that one’s innocent, childlike teshuvah (return to God) during the Days of Awe, opens within him a place to receive God’s love and light. A child’s lack of intellectual sophistication can actually enable him to have a deeper understanding, an understanding that gets into his bones.
We don’t live in an ideal world, yet. Still, we pray on Tu b’Shevat that our teshuvah during the Days of Awe—or any day or night of the year—be childishly pure and simple, full of innocence and received with love. Amen.
May all your prayers produce beautiful fruits. Amen.