Here's how the New Living Translation puts the answer to your question. I think it is pretty clear:
Mark 4:14 The farmer I talked about is the one who brings Gods message to others.
15 The seed that fell on the hard path represents those who hear the message, but then Satan comes at once and takes it away from them.
16 The rocky soil represents those who hear the message and receive it with joy.
17 But like young plants in such soil, their roots dont go very deep. At first they get along fine, but they wilt as soon as they have problems or are persecuted because they believe the word.
18 The thorny ground represents those who hear and accept the Good News,
19 but all too quickly the message is crowded out by the cares of this life, the lure of wealth, and the desire for nice things, so no crop is produced.
20 But the good soil represents those who hear and accept Gods message and produce a huge harvestthirty, sixty, or even a hundred times as much as had been planted."
I've seen this parable played out in many lives, including my own. The cares of life will always try and lure you away from God's Words of life, so we must be careful what we allow in our garden too. If we allow sin and weeds and thorns to live, then they may choke out some of the great blessings we have from God if we obey Him and keep ourselves pure so that we can be vessels put to good and often use by Him. I would rather be used by God than anything I can think of. Once you get a chance to serve Him, it is so sweet of an experience you want more and more to be used by Him and be closer.
The law is now written upon our hearts and is part of what the Holy Spirit brings to us. We do not obey from the outside in anymore, but from the love we have in our hearts we cannot break His law. Nobody who loves God will kill, lie, or continue in sin willfully.
2Ti 2:21 If you keep yourself pure, you will be a utensil God can use for his purpose. Your life will be clean, and you will be ready for the Master to use you for every good work.
Eze 11:19 And I will give them one heart, and I will put a new spirit within you; and I will take the stony heart out of their flesh, and will give them an heart of flesh:
Hebrews 8:6 But now hath he obtained a more excellent ministry, by how much also he is the mediator of a better covenant, which was established upon better promises. 7 For if that first covenant had been faultless, then should no place have been sought for the second. 8 For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah:
10 For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people: