3,902. Making the Incense

Hilchos Klei HaMikdash 2:1

The incense was mixed annually. This is a Torah obligation, as per Exodus 30:34: “You shall take spices....” Four of the necessary spices are named in the Torah and the rest were communicated orally to Moshe at Sinai.

Hilchos Klei HaMikdash 2:2

The need for eleven spices is a halacha l’Moshe miSinai. These were prepared in specific weights, after which Sodom salt and Jordan amber were added without weighing, as was the ingredient that caused the smoke to rise. Only a few key people knew the identity of this ingredient and it was transmitted as needed from person to person.