Faith's Greenhouse

Why is it contrary to our minds that tribulation and affliction are not the type of conditions that grow Faith? How is the issue that Paul writes of the Gospel of Christ? How do we see that trials don't produce faith, faith is a gift, but trials grow Faith? If a person compromises because of persecution does that reveal that there was no True faith to begin with? Why did they have to be warned about working and keeping up their obligations? Does error usually come from within? How does Christ cleanse and sanctify His people? What would make Christ's death to be in vain?