It has been said of this parable by many teachers in our various camps that each of these instances are representative of different types of believers, the mature and immature, the unfruitful (yet saved) and the fruitful. Yet the text of Matthew 13:3-9 (the parable itself) and Matthew 13:18-23 (the explanation of the parable by Jesus Himself) negates this faulty understanding.
There is only one who is saved in the end: the one who springs up by God’s power and produces fruit, not on account of the fruit itself that is produced (for we are saved by faith alone as Paul clearly articulates in Romans 4:1-25), but on account of the real, effectual, supernatural change that is made in a persons’ life by God’s Spirit in creating faith where there was none, being evidenced by the fruit (that is, authentic God-wrought faith is never alone (Martin Luther), but by God’s grace, it always produces fruit out of the faith He grants us, though we are still imperfect to be sure).
If you have true saving faith, there will be a sure change and shift in your life, a true love for the things of God, His Words, His actions, loving what He loves, hating what He hates, repenting of wickedness and leaning on Christ alone for your salvation and nothing else. That doesn’t mean there will not be struggling and fighting for these things against our wicked hearts. But it does mean that God’s power working in you will be plain and made obvious.