Hashem instructs Moshe to command Aaron and his sons, during their seven days of training, concerning their ongoing role in the Mishkan’s sacrificial rites.
“You shall not leave the entrance of the Mishkan for seven days, until the day when your days of inauguration are completed: for you shall be inaugurated for a seven-day period.” (Sefer Vayikra 8:33 rendered to English in the Artscroll Stone Chumash)
What us the connection between the this seven day period of learning their avodah in the Mishkan (Shivat Yemei Hamiluim — Sefer Vayikra 8:30-36) and the seven days of Sheva Brachot?
Chabad.org on this weeks Torah portion:
Hashem commands: “A continuous fire shall burn upon the altar; it shall not go out.”
Vayikra 6:5 rendered to English in the Artscroll Stone Chumash:
“The fire on the Mizbeiyach shall be kept burning on it, it shall not be extinguished…”
Shem Mishmuel now brings from a gemara a description of the ideal marriage with sources (pages 274-275) :
“Rabbi Akiva expounded: a man and a woman, if they so merit, the Divine Presence rests between them….” (Shem Mishmuel citing Sotah, 17a)
“The Divine Presence rests between them” — for He splits His Name and rested it between them: a yud in ish (man) and a hei in ishah (woman).
By way of explanation, the Hebrew word for “man,” ish, and the word for “woman,” ishah, each consist of the word eish (fire) plus one of the letters of the Divine Name…
This name [yud and hei] expresses the conjunction of the physical world and the spiritual world, as Chazal tell us: Olam HaZeh [this world] was created with a hei and Olam HaBah [the world to come; spiritual world] was created by a yud.
Just as during the seven-day training period for Aaron and his sons, Hashem commanded them concerning maintaining a continuous fire on the Mizbeiyach, Sheva Brachot for the Chattan and Kallah are the recognition of their Beit HaMikdash Ma’at and the continuous fire burning in unity — two halves of the same Neshama on their personal, spiritual Mizbeiyach with Hashem’s name resting between them.
To Avi and Racheli, Mazal Tov, and may your lives be always B’Simcha, with success in both Ruchni’us and Gashmu’is — with Yeledim: Torah, Chupah and Meisim Tovim, sources of Nachas to both your families and to all Klal Yisrael as you build a Bayit Ne’eman b’Yisrael — to AT LEAST 120 YEARS! L’Chayim, L’Chayim!