This interpretation considers "Nasīʾ" to be a synonym to the Arabic word for "intercalation" ("kabīsa"). It also suggests that every second or third year the beginning of the year was postponed by one month. The intercalation doubled the month of the pilgrimage, that is, the month of the pilgrimage and the following month were given the same name, postponing the names and the sanctity of all subsequent months in the year by one. The first intercalation doubled the first month Muharram, then three years later the second month Safar was doubled, continuing until the intercalation had passed through all twelve months of the year and returned to Muharram, when it was repeated. The Arabs, according to one explanation mentioned by Abu Ma'shar, learned of this type of intercalation from the Hebrew calendar used by the Jews, since intercalation was announced by the Nasi, meaning "prince", or "ruler". The Hebrew calendar commanded by Moses son of Amram, Mūsā bin ʿImrān, in Exodus 12, is necessarily lunisolar, because the lunar new year is fixed to the month of Aviv, or spring, and cannot rotate through the year.