Jesus. Yes, He is still the reason.

Kingdom Reproduction

Many of God's people stay miserable because they do not produce fruit. Jesus said He came that we might be able to have life and life more abundantly. But He also said that He is the vine, and you and I are the branches. If a branch does not bear fruit, He cuts it off. Now being cut off does not necessarily mean that you are dead, but it certainly does mean that you are not living the life He promised if you are cut off from Him.