XXI.(21) Οὐ βιαστέον τὴν φύσιν ἀλλὰ πειστέον πείσομεν δὲ τὰς ἀνάγκας ἐπιθυμίας ἐκπληροῦντες, τάς τε φυσικὰς ἂν μὴ βλάπτωσι, τὰς δὲ βλαβερὰς πικρῶς ἐλέγχοντες.
The newgreek translation, in the above ES, by persons from the greek gardens : “We must not force our nature but persuade it. Let us be convinced that we must fulfill the necessary desires, the natural if we are not harmed by them, and the harmful ones strictly checking them” . From Newepicurean.com The translation of Bailey , St. Andre and DeWitt : VS21. We must not violate nature, but obey her; and we shall obey her if we fulfill those desires that are necessary, and also those that are natural but bring no harm to us, but we must sternly reject those that are harmful. (Note: The translation by Peter St. Andre, found here, is “Nature must be persuaded, not forced. And we will persuade nature by fulfilling the necessary desires, and the natural desires too if they cause no harm, but sharply rejecting the harmful desires.” The St. Andre translation comports more closely with that followed by DeWitt in Epicurus and His Philosophy.)
1. In the above ES 21, I realized that you insist to take the meaning of the word «ελέγχοντες» as used by Epicurus which means “checking” with the meaning of “rejecting”. Nothing is rejected when the person has acquired that prudence on “how” to put his personal limits. Every translation has to go in consistency with the methodology of the Canon. Nothing is rejected before, if you do not first doing your personal measurement/calculation searching out the motives for all choice and avoidance, and banishing mere opinions, to which are due the greatest disturbance of the soul/mind that are against to the goal of pleasure.
2. In this ES21 when Epicurus says Nature he means our human nature as he is connecting it with our desires natural and necessary and the harmful ones.
3. Checking and not rejecting, and here is another translation http://wiki.epicurism.info/Vatican_Saying_21/
4. And a post of mine long time ago https://www.facebook.com/groups/EpicureanPhilosophy/permalink/840037286045233/