The apostle Paul uses the phrase "refresh the heart" some four times. This article wants to look at the use of the verb "anapauō" (with various meanings) in particular where it is combined with "pneuma" ("spirit") or "splanchna" ("bosom") in ancient Greek literary and non-literary sources. It concludes that Paul's use of the complete phrase (1 Corinthians 16:18, 2 Corinthians 7:13, Philemon 7, and Philemon 20) may have been a unique usage. He used it to indicate a Christian action that he highly commended.
Source: Tyndale Bulletin, 1996. 24 pages.