1 Peter 1:6–9 (NAS):  In this you greatly rejoice, even though now for a little while, if necessary, you have been distressed by various trials,  so that the proof of your faith, being more precious than gold which is perishable, even though tested by fire, may be found to result in praise and glory and honor at the revelation of Jesus Christ;  and though you have not seen Him, you love Him, and though you do not see Him now, but believe in Him, you greatly rejoice with joy inexpressible and full of glory,  obtaining as the outcome of your faith the salvation of your souls.
What does it mean to rejoice? In these few short verses, the Apostle Peter directs his readers into their need to rejoice in times of trials. For the apostle, periods of testing are seen as a “necessary” part of the believer’s life. And, while trials will come our way, they are seen by Peter as a time of rejoicing. Why? “So that the proof of your faith…may be found to result in praise and glory and honor at the revelation of Jesus Christ” (v. 7).
The Lexham Theological Wordbook defines the Greek verb agalliaō as “the state of experiencing such joy and gladness that it is expressed outwardly.” The use of the word in its various forms is often limited to biblical and ecclesiastical writings and is found in the Scriptures in instances relating to one’s present experience. It is agalliaō, which Mary experienced in Luke 1:47 stating, “and my spirit has rejoiced in God my Savior.” Likewise, it is the word used by the Philippian jailer of Acts 16:34, whose entire household receives salvation through the ministry of the Apostle Paul.
Peter shows us the need for rejoicing in times of trials such as these. The Scripture tells us that doing so is “proof of your faith” (v.7) and an expression of our belief in and love for Christ (v. 8). Regardless of your situation, “rejoice,” for God desires that you do so, and in doing so, you will be “obtaining as the outcome of your faith the salvation of your souls” (vs. 8). — Pastor Mark