The number seven is the biblical number for completion or fullness. The believer who keeps this feast is to keep it fully unto the L-rd and set himself aside completely to Him. A high sabbath in Hebrew is called a shabbaton. During Passover, there is an extra sabbath besides the weekly sabbath. These sabbaths are called high sabbaths.
Unleavened bread is used for consecration and separation.
It is also anointed with oil. The believers in the Messiah Yeshua are to be consecrated and separated to do the work G-d has called us to do and to live a life that is holy to Him. When leaven or yeast is placed in an unleavened batch of dough, the leaven puffs up the dough. Likewise, when we allow sin into our lives, it will puff us up in pride and arrogance. In the Bible, G-d referred to the leaven of different groups of people.