Question: "What does it mean to gird up the loins of your mind (1 Peter 1:13)?"
Answer: As Peter in his first letter exhorts Jewish believers to Christian conduct, he tells his readers to “gird up the loins of your mind” (1 Peter 1:13). Peter prefaces that important instruction with a “Therefore,” indicating that the exhortation rests on what Peter says prior.
Before his exhortation to gird up the loins of your mind, Peter provides a basis for the exhortation, as he commonly does in his letters. After a greeting (1 Peter 1:1–2), Peter extols the glory of God for God’s work in ensuring our salvation (1 Peter 1:3–5). The doxology in these few brief verses has at least eleven assertions of eternal security and the eternal nature of our salvation. In light of these statements of hope, Peter reminds us that we can rejoice even in the greatest of difficulties because we know that God will deliver on His promises (1 Peter 3:6–9). No matter what hardships believers in Christ face today, we know that He is faithful to ensure our salvation (1 Peter 1:9).
Peter adds that the message is both trustworthy and magnificent (1 Peter 1:12), and because of those factors and the assurances in prior verses, Peter exhorts his direct audience—and secondarily all believers in Christ—to gird up the loins of your mind (1 Peter 1:13). The phrase is clearly a figure of speech, as the mind doesn’t have “loins.”
Similar verbiage is used in the Septuagint (the Greek translation of the Hebrew Scripture) in 1 Kings 18:46 to illustrate what Elijah did immediately prior to outrunning Ahab to Jezreel. In that culture the loin cloth hung down, something like a slip, along with the robe, making it difficult to run. By wrapping or tying up the loin cloth and the robe, a person could run much more effectively. The same concept is mentioned in Ephesians 6:14, as Paul explains that the armor of God includes a girding of the loins with truth. For Peter to tell us “to gird up the loins of your mind” (1 Peter 1:13) indicates that he intends for us to be prepared for action; in fact, the NASB translates the phrase in 1 Peter 1:13 as “prepare your minds for action.” While this is not the word-for-word translation of the Greek phrase used (and perhaps not ideal), it does communicate what Peter seemed to imply by using the figure of speech.
Believers are exhorted to gird up the loins of your mind—to be prepared for action and in doing that to keep a sober or alert spirit. Ultimately, we fix our hope steadfastly on the future fulfillment of God’s grace through Jesus in our lives when Christ is revealed at His second coming (1 Peter 1:13b). The way for us to stand firm in the midst of difficulty and even persecution is by preparing for encountering those things and being well equipped with the knowledge of God’s promises for us. Peter is giving us the recipe for successfully encountering and persevering through difficulty—that we be clear on our assurance of salvation. We can trust in God, as He will keep the promises He has made to us.