The passuk states לא תוכל לאכול בשעריך מעשר דגנך ותירושך ויצהריך you are not able to eat in your gateways ma’aser of grain, wine, or oil. Rashi explains the passuk places a lo sa’aseh for eating these things out of the place allotted for them. Rebbi Yehoshua Ben Karcha says that a person is indeed physically able to do the action of the aveira, however he is not permitted to. Similarly at the end of the parsha it states לא תוכל לזבח את הפסח באחד שעריך אשר ה’… נותן לך you are not able to slaughter the Pesach offering in any one of your gateways that Hashem… gives you. The Seforno explains that although the Pesach offering in Mitzrayim was done without a mizbeiyach or Mikdash, the future generations need a mizbeiyach and Mikdash.
Onkelos translates both of these pessukim which start with the words לא תוכל as not permitted; you are not permitted to eat in your cities, and you are not permitted to slaughter in your cities. The Nesina LaGer explains that wherever the Torah states mitzvos which reflect an inability to do, Onkelos translates you are not permitted. Why does Onkelos translates לא תוכל as not permitted?
The Ramban explains that Onkelos teaches that one should not allow himself to do things which the Torah prohibits. The Torah states לא תוכל, “you are not able” to reflect the extreme distance one needs to separate from transgressing the prohibition. The Avi Ezer adds that the Torah reflects that a person should consider this as a great warning, as though he is unable to do it. A person is meant to internalize these mitzvos to become second nature, as though he is actually not able to do it, as an immovable peg wedged in or as an anchor rooted to its place.
The Rabbeinu Yonah brings that a person who repeats aveiros has a difficult time with repenting because his aveiros become as though they are permissible to be done. So too Chazal say once a person repeats an aveira it becomes כהיתר- as though he is allowed to do it. This is as the passuk states הנה דברת ותעשי הרעות ותוכל behold you spoke and you did bad things and you acted as though they were permitted. The word ותוכל means permitted, just as Onkelos translates תוכל permitted.
On Friday night we daven אוהבי ה’ שנאו רע which means “those who love Hashem hate bad.” I heard another explanation; according to the love one has for Hashem is how much he hates bad. A person who hates bad with a passion, reflects his intensive love for Hashem. He is constantly aware of Hashem, seeks to fulfill His mitzvos, and runs from transgressing aveiros. When a challenge faces him he won’t budge as it is so obvious this is bad, and he hates it so much, that he will not be drawn to sin.
May Hashem help us internalize the commands of Hashem to the point that we are unable to even think of transgressing them!