"Who are these and where do they come from?"
Every picture tells a story! When the apostle John saw this vision of such an immense multinational crowd he asked, "Who are these... and where do they come from?" They were all dressed in the same way — in white robes, freshly washed — no sign of stains or dirt — they were perfectly clean. These people are Christians from all ages and from all over the world. Some have indeed come through fiery trials for their faith, some have even died for their faith, and some have had to live out their faith in affluent circumstances but in a world that does not know God.
The Church of Christ in every age is going through the 'great tribulation'. The world hates it, especially when it is evangelising and seeking people to come to Christ. So we should not be surprised if we will encounter opposition as we live out our Christian faith day by day. But don't be discouraged. God will keep and watch over you. Your witness for him is not in vain and he will make sure you end up in that great crowd around the throne in glory.
Almighty God, I live in a dirty, unbelieving world. Help me to live each day as a faithful witness for you and give me a healthy longing for the clean, pure atmosphere of heaven. Amen.