Jewish weddings have been done under a canopy or chupah since biblical times. Psalms 19:6 describes the rising sun as being like a “bridegroom merging from his chupah”.
The chupah symbolises the first home of the bride and groom, a space that is theirs alone (albeit shared at that moment with the rabbi, parents, in-laws, bridesmaids, photographer etc). After the groom gives the bride the ring, they are not yet married until they have somehow demonstrated that they are now a couple.
There are a number of opinions in halachah about what action fulfills this. One view holds that it is yichud, being secluded together after the chupah. Another opinion is that it is the act of standing beneath the chupah.
Rabbi Aryeh Kaplan points out that the chupah is open on all four sides as it is simply a piece of cloth held up by poles or by four close friends of the couple. This reminds us of Abraham’s tent — the quintessential Jewish home — ready to receive guests from every direction.
Rabbi Julian Sinclair