Suppose the First Amendment had never been ratified. Could Congress pass a bill with the same wording, but also prohibiting then from repealing it?
A law can never have the force of the Constitution, since a law can always be overturned. A Constitutional Ammendment can also be overturned, but via a specific method outside of Congress alone. Also, since the Constitution has a higher standing than laws, it is more likely to be over-ridden by other Constitutional issues. The Constitution tends to come into conflict with itself fairly often, it is the balancing of different portions that makes Constitutional Law difficult. For example, a law about freedom to practice religion would not have as much weight as a constitutional statement about it.