One of the Bible's greatest truths is that God accepts us just as we are when we turn to Christ in faith -- even if our faith is small. Jesus told His disciples, "If you have faith as small as a mustard seed.... Nothing will be impossible for you" (Matthew 17:20).
Do you remember the man who asked Jesus to heal his son, who had been afflicted with seizures and other problems since childhood? The man admitted his faith was weak and he wasn't even sure Jesus could do anything -- but Jesus assured him He could, if the man would only believe. The Bible says that "Immediately the boy's father exclaimed, 'I do believe; help me overcome my unbelief!'" (Mark 9:24). Although the man's faith was weak, Jesus still healed the boy -- and the man's faith grew stronger.
Notice two things about this man. First, although his faith was weak, it was in the right person. Is your faith in Jesus, and in Him alone for your salvation? He came into the world for one reason: to bridge the gap between us and God -- a gap caused by our sin. He did this by becoming the final and complete sacrifice for our sins through His death on the cross.
Then notice that the man sincerely wanted a stronger faith -- and his faith grew as he was with Jesus. Don't be satisfied with a weak faith that comes and goes, but grow stronger in your faith by meeting with Jesus every day -- reading the Bible (which is God's Word), praying, worshiping and fellowshipping with other believers.