Verse 17. - In the fifteenth day of this month is the feast. The fourteenth day of Abib, or Nisan, the day of the passover proper, was not a feast, but a fast ending with the sacred meal of the evening. Only the ordinary daily sacrifice was offered on this day. Unleavened bread. מַצּות (mattsoth). Septuagint, ἄζυμα, unleavened cakes.

28:16-31 By the sacrifices enjoined in this chapter, we are reminded of the continued power of the sacrifice of Christ, and of our continual need to depend thereon. No hurrying employments, or perilous situations, or prosperous circumstances, should cause slackness in our religious exercises; but should rather stir us up to greater diligence in seeking help from, or giving thanks to the Lord. And all is to be accompanied with repentance, faith is the Lord Jesus, and love to him, and to produce true holiness in our conduct towards all men; otherwise God will abhor our most solemn services and abundant devotions. And Christ is able to supply the wants of every day, every week, every month, every year, every ordinance, every case.And in the fifteenth day of this month is the feast,.... Not of the passover, that was the day before, but of unleavened bread, which began on this day, and lasted seven days, Leviticus 23:6 which is what the Jews call the Chagigah:

seven days shall unleavened bread be eaten; see Exodus 12:15.