What is true of the Law is also true of the Bible generally. The Bible (both Old and New Testaments) exhibits this same characteristic of the sacred past being changed, adapted, rethought, and rewritten by people of faith, not because they disrespected the past, but because they respected it so much they had to tie it to their present. I'll go even farther. Without such changes over time, Christianity wouldn't exist. The Christian tradition depends on these changes over time--and some rather big ones at that.