“Wine Gladdens a Man’s Heart”
The blessings for bride and groom, the Sheva Berachos, commence with the blessing of “borei pri hagafen” over a cup of wine. The betrothal blessings begin with this blessing over a cup of wine as well.
Other mitzvos,too, such as kiddush for Shabbos and the Festivals, and havdalah on the nights following Shabbos and the Festivals, are also made over a cup of wine.
Blessings are recited over wine, as wine possesses the singular trait of arousing joy, as the verse states,1 “Wine gladdens man’s heart.” Our Sages comment:2 “Joy is only with wine.” So, too, writes the Chinuch about the nature of wine:3 “Man’s nature is very much affected by it: it satiates and brings him joy.”4
Thus, it is a mitzvah to drink wine on special joyous occasions. This is particularly so reagarding a wedding when it is a tremendous mitzvah to cause joy to the groom and bride, as the Tur states:5 “It is a truly great mitzvah to cause groom and bride to rejoice.” Furthermore, our Sages note:6 “There is no greater joy than that of a wedding.”
“When Wine Enters, Secrets Are Revealed”
An additional reason why wine is particularly connected to a wedding lies in wine’s singular nature of opening hearts and revealing that which had previously been concealed and masked. In the words of our Sages: “When wine enters, secrets are revealed.”
Its connection to a wedding:
A wedding affects and reveals the most concealed and hidden aspects — the souls of bride and groom that unite and are now revealed as one (as explained earlier at length). There is thus a clear relationship between a wedding and wine, which both reveal the “secret” and the “hidden.”7
[Additionally, Chassidus explains at length8 how the spiritual and Divine source of wine is truly lofty, and, at a wedding as well, truly lofty powers are granted to bride and groom.]
The cup of wine — the “cup of blessing” — is also linked to a wedding.
Chassidus explains9 that husband and wife are an allusion to the “cup of blessing”: the cup alludes to the wife and the wine that is within the cup hints to the husband.
The Jewish People — The Grapevine
A Jew’s soul (which is so affected by a wedding) and wine are connected from yet another standpoint:
Our Sages state:10 “The ‘grapevine’ refers to the Jewish people.” The reason for this is explained in Torah Or:11 “Wine is concealed within the grape, for the grape is round and wholly encompasses the wine within it. It is impossible to get at the wine without first squeezing and pressing the grape....
“So, too, it is impossible to reveal the soul’s hidden love for G‑d — which is as concealed as wine within the grape — without first squeezing. Thus it says: ‘Be exceedingly humble,’ [achieve a] ‘contrite and broken heart,’ of the degree and rank of ‘my soul is as dust to all.’12 When this is accomplished, the Divine soul is revealed.”