The number seven is a pretty important number in the Torah and, in this week’s special Sukkot Torah portion, it shows up quite a bit! Seven is understood as the number of completion. God finished the earth in six days and rested on the seventh, Sukkot is seven days of offerings, Shavuot is seven complete weeks after Passover (which is seven days), and of course there are many more examples. The argument for seven being the number of completion is pretty compelling, but I would argue that seven is also a number of great tension.
Think of the major musical scale: Do Re Mi Fa So La Ti Do. If you were to hum it out loud and simply stop at Ti, your ear would likely urge you to resolve the sequence and that would bring us back to Do (oh, oh, oh). The point is, the same applies in Judaism regarding the numbers seven and eight.
If we think of creation, God rested on the seventh day, but it is on the eighth day that humanity joins in partnership with God. Shavuot is seven complete weeks after Passover and is celebrated on the fiftieth day, which means the holiday is celebrated at the beginning of the eighth week. An ox, sheep, or goat stays seven days with its mother and from the eighth day, the animal can be sacrificed. A boy is born and only on the eighth day is the circumcision performed. Sukkot is only seven days, but the eighth day is to be a sacred occasion.
This is all to say that the eighth day is a lot like the first day, but totally different at the same time. Just like in the musical scale, there are resolution and new beginnings with the number eight. With eight, we begin again, we begin anew. Perhaps that is one reason why our High Holiday season takes place in the seventh month of the year and Heshvan, the month with no holidays (known as bitter Heshvan), is the eighth month… an opportunity to start anew.