What is the tense of "Rachatzu Hizaku"?
Rashi: They are commands, for Rachatzu has a Patach under the Reish. With a Kamatz, it is past tense.
What should you wash and make clear?
Radak citing his father: Wash the heart and make it clear.
Malbim: Wash the stains of previous sins, via regret and abandoning sin. Mere washing and rinsing is not enough. You must make it very clear, until the stain totally departs. I.e. repent amidst love, until the sins become merits.
Why does it say "Hasiru Ro'a Ma'aleleichem"?
Malbim: Regret [and abandoning sin] suffices for sins Bein Adam la'Makom; nothing remains from them. For sins Bein Adam l'Chavero, you must remove the deeds from in front of My eyes - return the theft or overcharging, pay for wounding, and appease the slandered.
What is the meaning of "Chidlu Hare'a"?
Rashi: Refrain from evil deeds. "Hare'a" is like Lehara. There is no need for the prefix Mem (mi'Lehara), for [the infinitive] is used with Chidlu [without a prefix], e.g. "v'Chadal La'asos ha'Pesach" (Bamidbar 9:13), "Ad Ki Chadal Lispor" (Bereishis 41:49), i.e. he refrained from counting and from doing. Also here, refrain from evil.
Radak: Refrain from doing evil to your colleague.
