l'ilui nishmat R' Avraham ben Yona Ya'akov

“And his voice was will be heard when he comes into the holy” (28; 35)

In the Mesorah on this verse it says that the word v’nishma (and we will hear/ and it/ he will be heard) appears three times in Tanach. Once here, once in Parshat Mishpatim in the phrase na’aseh v’nishma (we will do and we will hear), and once in Megillat Esther v’nishma patshegen hamelech (the decree of the king was heard). It is not clear what the connection is between these three verses.
Perhaps we can explain that the Mesorah here is hinting at the prayer that the Cohen Gadol said after coming out of the Holy of Holies. The verse says “He will atone for himself, and his brothers and all of Israel”. He will atone for himself, for all the other Cohanim (his brothers) and one for all of Israel.
This is what the Mesorah is hinting to us. “His voice will be heard” – his own prayer. “We will do and we will hear” – for all the Cohanim, who have the task of serving G-d in the Temple. “The decree of the king was heard” was a decree for all of the world and all of klal Yisrael.

“You shall make an altar for offering incense” (30; 1)

It is very strange that this parsha is here, when logically I would have expected it in parshat Terumah, where we have the instructions for all the other utensils in the Mishkan. Parshat Tetzaveh deals only with the clothes of the Cohanim, so this instruction seems very out of place.
Perhaps we can say based on the explanation in Parshat Korach. Korach and his followers were arguing and challenging the rights of Aharon to be the Cohen Gadol. It was through the incense that the argument was resolved (when Aharon’s incense offering was accepted by G-d, and all the challengers were killed). This showed that Aharon had the honour of being Cohen Gadol based on Divine decree, not nepotism. This is explicit in the verse (Bamidbar 17; 5) “An eternal remembrance for the Children of Israel that nobody who is not a descendent of Aharon should offer the incense”.
Since it is in this Parsha that Aharon becomes sanctified to be the Cohen Gadol, that is why the mitzvah of building the incense altar comes in this parsha – to show that through the incense Aharon’s authority was Divinely sanctioned, and nobody has the rights to challenge it.
We can give another allegorical answer as to why it does not appear in parshat Terumah. Rav Ya’abetz writes in his siddur that the reason we recite ‘pitum haketoret’ (the recipe for the incense) at the end of Shacharit is for the same reason that we bring out the incense at the end of a meal (and recite the blessing over it – Talmud Brachot 42b). The Talmud’s word for the incense after a meal, mugmar is the Aramaic translation of the Torah word for incense ketoret as we see from Shir Hashirim (3; 6) “From the incense (ketoret) of myrhh and frankincense. The Aramaic translation is m’tagmara (mugmar). Therefore in this parsha which deals with the clothing, and after the preceding parsha that deals with the utensils, and the order of the consecration of the Cohanim, comes the incense, to show that everything ‘smells good’ and will find favour with G-d.
But it is not at all clear why we use the word mizbeach (altar) in regard to the incense altar. The root of the word mizbeach is zevach meaning animal sacrifice. Why does the Torah use this word for the implement that was used for offering the incense? This implement should be called a maktir.
Perhaps this is why the Sages explain allegorically that the word mizbeach is an acronym for mechila (forgiveness), zechut (merit), bracha (blessing) and chaim (life) (Vayikra Rabba). This teaches us that the incense brings all these good things to the world. See also Talmud Ketubot 10b.