Matthew 14:28-31 And Peter answered him and said, Lord, if it be thou, bid me come unto thee on the water. And he said, Come. And when Peter was come down out of the ship, he walked on the water, to go to Jesus. But when he saw the wind boisterous, he was afraid; and beginning to sink, he cried, saying, Lord, save me. And immediately Jesus stretched forth his hand, and caught him, and said unto him, O thou of little faith, wherefore didst thou doubt?
The reasons people fall into doubting their salvation can generally be summed up in two categories:
1. The person really isn’t saved.
2. The person is saved but has lost confidence in his or her salvation for some reason.
There are a number of reasons why a person might think they are saved when they are not, then eventually come to rightly doubt their salvation.
There are people who confess faith in Christ without understanding what they are doing and why. This may happen because others are doing it or it seems like the right thing to do. Perhaps they are afraid to go to hell, or they just want to go to heaven, but they don’t really understand what it means to repent and believe on the Lord Jesus Christ. They don’t have a concept of sin and righteousness and judgment and they have not been convinced by the Holy Ghost.