You are imagining a division in the word, and it is not there.
With all due respect, God says there is. And He says that without rightly dividing His word of truth, or not dividing it at all, men will be unapproved workers for Him, no matter how hard they strive. A simple example of this would be those who, now, are striving to bring the Kingdom Gospel to fruition and establish this Kingdom on earth for Him, instead of striving to preach the Gospel of the Grace of God, during this age of the grace of God. Both of these are truths, but only one is truth for this age we are living in, in God’s plan for mankind. Both of these are for our understanding and study, but they are not both for duty to fulfill today. To be striving to bring men into a Kingdom that only Christ, the Messiah, can and will establish at His return, is to try in vain to turn that program into a program that is based not only opposed to the program for today (”For BY GRACE are ye saved through faith, and that NOT OF YOURSELVES, it is the GIFT OF GOD, NOT OF WORKS, lest any man should boast.”), but turns grace into a lie. And God’s word of truth for today into a confusing lie. (Hence the ongoing argument between Paul and James). Hence the Catholic Church and her works, belief system, traditions, and performance-based salvation that is built on a lie that she and she alone can establish God’s Kingdom on earth for Christ. She has taken God’s truth for Israel, tried to hijack it, make it her own and the result is, she had turned God’s truth for Israel into a lie for the Body of Christ.