סימן כט סעיף ט
וְכֵן אֵין לְהִתְקוֹטֵט בִּשְׁבִיל אֵיזֶה מִצְוָה כְּגוֹן, לְהִתְפַּלֵּל לִפְנֵי הַתֵּבָה, אוֹ לַעֲלֹת לַתּוֹרָה וְכַדּוֹמֶה, כִּדְמָצִינוּ בְּלֶחֶם הַפָּנִים, אַף שֶׁהוּא מִצְוָה לְאָכְלוֹ, שָׁנִינוּ הַצְּנוּעִים מוֹשְׁכִים יְדֵיהֶם וְהַגַּרְגְּרִין חוֹטְפִין וְאוֹכְלִין. (אוֹרַח חַיִּים סִימָן נ"ג)
Neither should you quarrel for [the right to perform] a mitzvah, such as to lead the congregation in prayer, or to be called up to the Torah, or the like. Just as we find it with the Show-bread,30Lechem hapanim, literally “bread of the face” (see Lev. 24:5,8). It was so called because the sides were bent up. The loaves had the shape of a box with the ends removed. Twelve loaves were placed on the Table in the Sanctuary. They were arranged on a frame in the two stacks of six loaves each. Each Shabbos the loaves were replaced by fresh ones, and the old ones, which miraculously retained their freshness, were divided among the kohanim. that although it was a mitzvah to eat of it, yet, we are told, "The modest used to give up their share while the gluttons used to grab and devour it."31Yoma 39a.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)