At Shabbos Minchah we say the passuk “va’ani sefilasi lechoh Hashem…” According to the Medrash, it is an expression of thankfulness that we are different from the non-Jewish world when celebrating: They eat, drink, make merry, and act disgracefully, while we sing praises of Hashem, and pray and study Torah. This is especially brought out at Shabbos Minchah, after we eat and rest, we occupy ourselves with Torah and davening Minchah. It is said even when davening alone. It should be said standing.
Shabbos Bulletin Parshas Chukas 5779
About the Author: Lev Seltzer
Lev Seltzer has been a member of Beis Tefillah from just a short time after its founding. He currently manages the BTYA.org website, and can be found every morning in the BTYA "Vasikin Room" where he is the gabbai of the minyon.