In 1513 B.C.E., when those tribes became a nation, Jehovah gave them a system of laws that included various annual festivals.
وَكَمَا قَالَ ٱلرَّسُولُ بُولُسُ ،‏ كَانَتْ هٰذِهِ ٱلْأَعْيَادُ ‹ ظِلًّا لِلْأُمُورِ ٱلْآتِيَةِ › .‏