Repetitio mater studiorum est. "Repetition is the mother of all learning." The Apostle Paul understood this. Under the inspiration and superintendence of the Holy Spirit, Paul constantly repeated the foundational truths of biblical doctrine, and he did so not only within each of his epistles but sometimes within the same sentence. The clearest example of this is found in Paul's epistle to the Ephesians. As he unfolds the glorious mystery of our salvation, Paul reiterates the phrase "in Christ" or "in Him" continually throughout the first chapter, and nearly ten times in verse 3–14, which is one long sentence in the original language. Several years ago as I preached through Ephesians chapter 1, I explained to our congregation that if they were only to remember one truth from our study of Ephesians, that it should be the phrase "in Christ," which is a shorthand way of remembering one of the most foundational aspects of salvation—our union with Christ.