1 Peter 1:7

7 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;

Their trials will be used to test their faith to see if it is genuine; and if it is, it is something that will bring them much praise and glory and honor when He rewards them (1 Thess 4:13-18; 1 Cor. 3:13-14).