The Feast of Unleavened Bread (Leviticus 23:6-8).
“And on the fifteenth day of the same month is the feast of unleavened bread to Yahweh. Seven days you shall eat unleavened bread.”
Passover was immediately followed by the Feast of Unleavened Bread (Exodus 12:15-20; Numbers 28:16-25) which began when the moon was full. This was probably an old feast adapted for the new situation of fleeing from Egypt. For seven days unleavened bread was to be eaten as a reminder of the speed with which they had had to leave Egypt. But the unleavened bread may also have previously celebrated a newly arrived harvest when the old leavened grain would no longer be required. It may well have once celebrated the beginning of the barley harvest when the Patriarchs were in Canaan, and have been continued by long custom as a feast to celebrate even when things were different in Egypt (old habits die hard), possibly being adapted to connect with the wheat harvest or with lambing or some other aspect of life in Egypt. The old customs would continue although their significance would be reinterpreted. Once they reached Canaan it would be re-established with its old significance (Leviticus 23:10-11).
“In the first day you shall have a holy convocation. You shall do no servile work.”
The first day of that week was to be a sabbath, no matter which day it fell on (Exodus 12:16), a day when no servile work was done. The minimum necessary so that they could eat and celebrate the feast was allowed. This restriction was possibly not quite as rigid as for the regular Sabbath.
“But you shall offer an offering made by fire to Yahweh seven days. In the seventh day is a holy convocation, you shall do no servile work.”
The seventh day was also ‘a holy convocation', a further sabbath (and the regular Sabbath would fall somewhere during the seven day period). Each day of the feast an offering by fire would be made to Yahweh.
This feast is a reminder to us of the need to remove from our lives all the leaven of wickedness and malice and to partake of the unleavened bread of sincerity and truth (1 Corinthians 5:7-8). We are to purge out the old leaven so that we might be like a new lump, totally unleavened. We are also to beware of the leaven of false teaching, the ‘leaven of the Pharisees' (Matthew 16:6; Matthew 16:12), and of worldly constraint, ‘the leaven of Herod' (Mark 8:15).