One should not recite a blessing - this ruling comes to rule out what is taught (Niddah 51b), that in the Land of Israel, they would recite the blessing: “[Blessed are you…] who sanctified us with his commandments, and commanded us to guard his laws”, upon taking off their Tefilin for the night, being that they were of the opinion that nighttime is not the time for wearing Tefilin (even biblically), and they derive this from what it says in the verse: “And you shall guard this law in its proper time, from day to day” (Exodus 13:10) - and not at night - however according to us, there is no reason to recite a blessing upon removing the Tefilin for the night, being that we explain that verse to be referring to a different law, and it is therefore permissible to keep the Tefilin on at night (if he had them on before nightfall, and did not remove them afterwards) only it is forbidden to put them on once night begins, because the Rabbis decreed not to put them on at night, in order that he should not fall asleep, and pass gas while wearing them

Twilight - meaning, although we hold that Shabbat and the festivals are not times that Tefilin is to be worn, and if one were to put them on then, for the sake of fulfilling the Mitzvah, he would be transgressing the prohibition of “do not add [on to the commandments]״, nevertheless, being that if one were to put them on without the intention of fulfilling the Mitzvah, he would not be transgressing a biblical prohibition, only according to some, it is was decreed by the Rabbis not to do so, in order that one should not come to walk with them on in a public domain on Shabbat, and therefore no blessing is to be made upon removing the Tefilin, being that there is no Mitzvah to remove the Tefilin per se, and it is done only because of the rabbinic decree mentioned above.