Thanks for both of your responses. I will try to spend some time on this late this evening. If you might give me the direct reference to Irenaeus, it would help. I am fairly certain that I have all of his writings here at work, but I would only want to bring one volume home.
Here is a discussion on the subject at an on-line site
"For all things had entered upon a new phase, the Word arranging after a new manner the advent in the flesh, that He might win back to God that human nature (hominem) which had departed from God; and therefore men were taught to worship God after a new fashion, but not another god, because in truth there is but “one God, who justifies the circumcision by faith, and the uncircumcision through faith.”