All the 7 Rainbow colors representing each day of creation and
when combined produce white color. It is a known fact that
shining white light through a prism produces the rainbow colors.
White signifies purity and goodness. No wonder on the 6th day,
God declared that everything he has created during the 6 days of
creation as very good and blessed it on the 7th day. Genesia1:31
God saw all that he had made, and it was very good. And there
was evening, and there was morning—the sixth day. Genesis2:1
Thus the heavens and the earth were completed in all their vast
array. 2 By the seventh day God had finished the work he had
been doing; so on the seventh day he rested [a] from all his
work. 3 And God blessed the seventh day and made it holy,
because on it he rested from all the work of creating that he
had done.