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SABBATH, DAY AFTER THE (Heb. māḥărat hashshabbāt). A term of disputed meaning (Lev. 23:11, 15) occurring in connection with the feast of the Passover. The Sabbath referred to is not the weekly Sabbath but the day of rest, the first day of holy convocation of the Passover, the fifteenth Abib (Nisan). As a day of rest on which no laborious work was to be performed (v. 8), the first day of the feast is called “Sabbath,” irrespective of the day of the week upon which it fell. Thus “the day after the Sabbath” is equivalent to “the day after the Passover” (Josh. 5:11).
Unger, M. F., Harrison, R. K., Vos, H. F., Barber, C. J., & Unger, M. F. (1988). The new Unger's Bible dictionary. Revision of: Unger's Bible dictionary. 3rd ed. c1966. (Rev. and updated ed.). Chicago: Moody Press.