Yes. Absolutely.
The parable of the sower of seed has great meaning, but it does not mean that there is any sin that Christ will not forgive. Rather, it is a parable about those who hear the Word and reject it, or allow the Word to die in their hearts.
I agree with that any sin can be forgiven if one is in Christ. And yes, as Mrs. Don-o said, repentance is what we are called to do by Christ. You can look up the number of time He Himself said to people "Repent." He would usually say this in the context that he Kingdom of God was here.
I also agree that this is a very tough subject, for one basic reason. We all sin. Even after we are saved by Jesus Christ, and the Holy Spirit indwells with us, we still sin. Now, James Chapter 2 tells us clearly that our faith via Christ changes us. If we are not changed by the Holy Spirit in our lives, our faith is probably dead.
However, we are not saved by anything we "do." Good works are a manifestation that we are saved. Just as we truly love our brothers in sisters in Christ and the Jewish people if we are saved. These are significant signs that we are saved. When we sin, we feel terrible if we are in Christ. Because the Holy Spirit grieves us to repentance.
Have you come across people whose consciouses are so seared they care not a whit who they hurt, or what they do? Of course you have. These are the wicked, and we deal with them every day. But God brings those in Him back into the fold - gently, but also with judgment at times. God's first and foremost concern is not our comfort here on earth, but our ultimate salvation.
Here is what cuts me to the heart about sinning (and when I sin). Hebrews 2: 1-4.
"We must pay the most careful attention, therefore, to what we have heard, so that we do not drift away. 2 For since the message spoken through angels was binding, and every violation and disobedience received its just punishment, 3 how shall we escape if we ignore so great a salvation? This salvation, which was first announced by the Lord, was confirmed to us by those who heard him. 4 God also testified to it by signs, wonders and various miracles, and by gifts of the Holy Spirit distributed according to his will."
What the author of Hebrews (speaking through Holy Spirit) said what that we must be careful - because to know Christ and reject salvation is grave indeed.
So that when I sin, I feel worse than I could imagine, and I must confess that sin and seek forgiveness.
This is serious business. Has my salvation left me if I fall into sin? I don't believe so, although some may disagree with me. Here is why I believe I cannot lose my salvation:
Romans 8: 38-39.
"38 For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, 39 neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord."
I think what the author to this piece is saying that we should not go about sinning great sin beforehand, thinking that we can just cover everything up. For one thing, all believers will sit on the judgment seat of Christ. This is not the same judgment the unbelievers have - we won't face the Great White Throne Judgment. Christ saved us from that. But we will be called into account for our actions, good and bad. We may lose rewards or crowns in heaven on account of what we have done, or not done. Every work will be brought into account. This is sobering.
Here is what encourages me though. What did that thief who was crucified next to Christ do to earn his salvation in paradise? No works. He was saved because he asked Jesus to save him. And Jesus did, with one of his last, dying breaths.