Why do Christians wilt and fall away when adversity comes?
The major reason is that they lose hope. They can’t see the promises immediately and so their hope wanes. Why does hope fade? Because the young Christian stops believing what they have been told about God and His plan.
Precious Sheep Of Renown 
Good post! But I believe it goes even deeper. When the Apostles taught Christ teachings, they mentored them. Teaching them the way. Today, many Churches throw you into a class but you’re not really mentored. Because those who truly repent will be given a new heart and God’s Spirit. But if these new Christians are not taken by the hand and led by true men of God, chances are they will fall away. But read Romans 8:9, this could be a big part of the problem. Thanks for sharing and just my thoughts. God bless you…Robin