In the Lord's parable of the sower the third kind of soil that seed fell upon was the thorny ground. We know all to well the problems from thorns and thistles and weeds in our own gardens.
These are the crops that come up naturally out of the earth - though it wasn't always so. This began when sin entered the world through the first man Adam, and brought God's curse on the ground. "...Cursed is the ground for thy sake...Thorns and thistles shall it bring forth to thee..." (Genesis 3:17, 18). It was a reminder of the condition of sin that had entered the human heart. The conditions in the ground mirror the spiritual condition of human hearts. Now the thorns of sinful living comes naturally out of the heart of all mankind.
"For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders" (Mark 7:21). When the Word of God is heard, and God's offer of salvation through His Son is realized, there should be a wholehearted response. The soul should gladly turn from sin and commit itself to the resurrected Saviour in faith.
However, there are those who don't really want to give up their sins. Jesus' interpretation of the thorny ground in the parable is a warning that His salvation does not go along with continuance in sin. "And the cares of this world, and the deceitfulness of riches, and the lusts of other things entering in, choke the word, and it becometh unfruitful" (Mark 4:19). Christianity is only received meaningfully when the sin issue is dealt with in the human heart.
The problem is still with us today. Very many are so taken up with illicit pleasures or even just everyday worldly business that they have no real interest in God's offer of His Son. Salvation is free and can bring forgiveness to any sinner, but that person must mean business with God.