Luke 8:15, "But
that on good ground are they, which
in an honest and good heart,
having heard the word,
keep it, and bring forth fruit
First of all, one must hear the word. Now, it does not take a rocket scientist to understand from reading the Bible that not all of God's children are going to hear the word by the gospel. Many of God's children have lived out their natural lives and died without having ever heard it. So, to bring forth bountiful proper fruit, one must hear the gospel. Many of God's children do not hear the gospel because it's unavailable. Most of them do not hear it, because they are too lazy to get out there and hear it. If one believes the gospel is necessary for eternal salvation, then they have a major problem combating the affliction of laziness (even before they address a possible stony heart). Therefore, 30 fold is those that hear the gospel.
Next is those that keep it. Paul told the Corinthians that they could save themselves if they kept the gospel that he preached in memory and stand fast in it. They could save themselves from ignorance and walking in ungodliness. The gospel addresses certain things that we need to be doing in our lives. These things keep us out of the ditches (on both sides). Therefore, those that keep it bring forth fruit 60 fold.
Lastly, those that bring forth fruit in patience are those that hear the gospel, keep it, and labour patiently in the vineyard of the Lord. It takes diligence and dedication to pull the word out every day to read and study. It takes patience to let go of grudging and angry thoughts. It takes patience to keep the devil from coming to church with you on Sunday. It takes patience to live peaceably with all men. Those that preach a Sunday religion are off by 6/7 of the whole. These patient people are the ones bringing forth fruit 100 fold. May we ever be found faithful bringing forth as much good fruit as possible in the service of our Lord.