וְזָ֣כַרְתָּ֔ כִּי־עֶ֥בֶד הָיִ֖יתָ בְּאֶ֣רֶץ מִצְרָ֑יִם עַל־כֵּ֞ן אָנֹכִ֤י מְצַוְּךָ֙ לַעֲשׂ֔וֹת אֶת־הַדָּבָ֖ר הַזֶּֽה׃
And you shall remember that you were a slave in the land of Egypt; therefore I command you to do this thing.
Chazal source (beyond the TT-numbered units of the main ring): Sifrei Devarim / Rashi on Devarim 24:18 & 24:22 (parallel formulations of the slavery reminder for the agricultural gifts).
Lemma: וְזָכַרְתָּ כִּי עֶבֶד הָיִיתָ.
Sefaria — Sifrei Devarim · Rashi ad loc.
וְזָכַרְתָּ כִּי עֶבֶד הָיִיתָ בְּמִצְרַיִם – עַל מְנָת כֵּן פְּדִיתִיךָ, לִשְׁמֹר חֻקּוֹתַי אֲפִלּוּ יֵשׁ חֶסְרוֹן כִּיס בַּדָּבָר.
English: “You shall remember that you were a slave in Egypt” — on that condition I redeemed you: that you observe My statutes even when there is monetary loss involved.
On the daf / in context: The repeated reminder (24:18 and 24:22) frames the laws of the forgotten sheaf, gleanings, and leftover grapes. Rashi and the midrashic tradition treat the redemption from Egypt as the explicit condition for observing these mitzvos of kindness to the stranger, orphan, and widow, even at personal cost. Parallel Sifrei material on the agricultural gifts reinforces the same rationale.
Derash on the repeated slavery formula (Sifrei / Rashi) — the verse supplies the reason and the condition of the preceding agricultural mitzvos.
The obligation to leave the forgotten sheaf, gleanings, and leftover produce for the poor is grounded in the memory of slavery in Egypt and is required even when it involves monetary loss; the redemption itself was conditioned on observing these statutes.