And moreover, whenever it says אחת מכל, (like ועשה אחת מכל מצות השם - and does through error any one of all the things which the LORD his God has commanded not to be done¹³⁸), the word אחת is superfluous; the letter מ in the wordמכל already implies “any one of” (like אשר יעשה מכל התועבות - For whosoever shall do any of these abominations¹³⁹). And it is always homiletically interpreted that there is an obligation with respect to each and every one of the things that God has commanded.

Leviticus 4:22-23 says,אשר נשיא יחטא ועשה אחת מכל מצות יהוה אלהיו אשר לא תעשינה בשגגה ואשם. או הודע אליו חטאתו אשר חטא בה והביא את קרבנו שעיר עזים זכר תמים(When a ruler sins, and does through error any one of all the things which the LORD his God has commanded not to be done, and is guilty: if his sin, wherein he has sinned, be known to him, he shall bring for his offering a goat, a male without blemish). The word אחת is there to teach that for each sin, the ruler is obligated to bring a sin-offering.

footnotes: ¹³⁸ Leviticus 4:22. ¹³⁹ Leviticus 18:29.