When people are tempted and still continue strong, they should be happy. After they have proved their faith, God will reward them with life forever. God promised this to all those who love him.
These troubles come to prove that your faith is pure. This purity of faith is worth more than gold, which can be proved to be pure by fire but will ruin. But the purity of your faith will bring you praise and glory and honor when Jesus Christ is shown to you.
These enemies of Christ were in our fellowship, but they left us. They never really belonged to us; if they had been a part of us, they would have stayed with us. But they left, and this shows that none of them really belonged to us.
Like someone who heats and purifies silver, he will purify the Levites and make them pure like gold and silver. Then they will bring offerings to the Lord in the right way.