The 20th mitzvah was to build the Temple, so the mitzvot continue here with more commandments dealing with the Temple and Temple services.
Summary: The 21st positive mitzvah of the Torah is to revere and respect the Holy Temple in Jerusalem, while the 22nd is to guard the Temple at all times. The next mitzvah is for the Levites to serve in the Temple, and the one that follows is for the Kohanim to wash their hands and feet before beginning their Temple services. The 25th mitzvah is for the Kohanim to light the Temple menorah, while the 26th is for the Kohanim to bless the congregation. The 27th is to display the “showbread” (lechem panim), a set of twelve loaves representing the Twelve Tribes of Israel. The 28th mitzvah is to light the incense (Ketoret) in the Temple. The 29th is the mitzvah of esh tamid, to maintain a “perpetual flame” burning on the Temple altar. The 30th mitzvah is to remove the leftover ashes from the altar daily. The 31st is to keep any person in a state of impurity away from the Temple. The 32nd is to honour the Kohanim, while the 33rd is to clothe the Kohanim in the special priestly vestments, as specified in the Torah. The 34th is to properly carry the Ark of the Covenant whenever it needed to be transported, and the 35th is to anoint the priests with the special anointing oil (shemen hamishchah). The 36th mitzvah is to divide the Kohanim up into various “watches”, each serving in the Temple for a two-week shift. On the holidays, however, all the Kohanim would serve together. Generally speaking, a Kohen is forbidden from going to a cemetery or being around a corpse so as not to be defiled by the impurity of death. However, the 37th mitzvah allows for a Kohen to mourn their immediate family members and become impure. The 38th mitzvah is that a Kohen Gadol, the “high priest”, if he needs to get married, must marry only a virgin. The 39th mitzvah is to perform the daily sacrificial offering, which was two sheep per day, one in the morning and one in the late afternoon. The 40th mitzvah is to offer the minchah, the “meal-offering” of grains.
Insight: Of the 613 commandments, a whopping 314 require the Temple to be performed! That leaves only 299 commandments that we are able to fulfil today, without the Temple. Having said that, the Sages instituted many halakhot to parallel the Temple services. For example, the 21st mitzvah noted above, to revere and respect the Temple, can be applied to revering and respecting the synagogues – which are our places of worship and the closest things we have to a “Temple” today. The 24th mitzvah for the Kohanim to wash before serving is related to netilat yadayim, when we wash our own hands before eating a meal, since the Sages state that a person’s meal table is like the sacrificial altar (see Berakhot 55a and Chagigah 27a). While we no longer have the Temple menorah, we do have the candle-lighting of the Chanukah menorah, as well as the weekly candle-lighting to usher in the Sabbath (for more on this, read: ‘Origins and Mysteries of Shabbat Candles‘). The Kohanim still bless the Jewish people in our prayer services (the 26th mitzvah), and before this the Levites wash their hands, partly in fulfilment of the 23rd mitzvah. Even the sacrificial offerings have parallels, as our prayer services have been instituted corresponding to the Temple offerings. Each prayer that we offer Hashem is likened to a sacrifice, as the prophet Hoshea (14:3) said: “…we shall offer the cows with our lips.” And so, although we cannot fulfil many Torah mitzvot directly, we can fulfil them indirectly through the observance of their corresponding halakhot.