But because of your hard and impenitent heart you are storing up wrath for yourself on the day of wrath when God’s righteous judgment will be revealed.
In order to have salvation, we need to be saved from something. So what is it that we are saved from? The obvious, but I believe wrong answer, is sin. While God cannot stand sin, I believe that there is more to it than that, and this verse hits it hard.
But because of your hard and impenitent heart This is what we need salvation from, the heart that causes sin. The hardened and unrepentant heart that says, I will not, I cannot yield to God and His ways. The word "hardened" carries with it the image of calluses. We are somewhat hardened by our constant exposure to the world that we live in, especially when we don't stop to view things from God's perspective. When we see others who have more or don't suffer as we do, it can create feelings of hurt. These feelings, if not dealt with, can and will create a toughening of our protective shells.
Two illustrations quickly come to mind. One shows what an idiot I can be, so I will share that one.
I was working in the garage on a project and got my thumb too close to the blade on the table saw. My first response was to say, "It is merely a flesh wound." A throbbing, painful, bloody flesh wound. So I go in the house, clean it up and bandage it. My wife thinks I should go to the emergency room, but it don't. 24 hours later, I am in the med center getting stitches. By now the wound has begun to heal, and the doctor tells me that I should have come in sooner. He goes on to state that I will probably have a permanent numbness in the tip of my thumb, which I now do. The tip of my thumb has no feeling, which is dog-gone irritating when trying to play video games. Not to mention, the rest of my thumb feels sensitive around that area when I am out in the cold.
My thumb was cut, and because I did not treat it correctly, the inside has a permanent callus that has no feeling. Because our heats have lost their feeling, we do not repent. Why change when there is no feeling of wrongdoing? And what a better picture of our current world than to say they feel no wrong! Not only do they feel no wrong, but they berate those who do. Christians who stand for something (and not always in the best ways, I will admit) are viewed as intolerant. Abortion, homosexuality, lying, and all of the rest of the commandments are viewed as outdated.
Even within the church, and that is to whom Paul is writing, there is this intolerance of others who do not see things as we do. So just like the Pharisees, we put heavy burdens on them that we ourselves are unwilling to carry. We pressure people to tithe, stop drinking any alcohol, don't go to R rated movies, dress a certain way (especially on Sunday), etc. Not that these things are bad, but they do not ensure salvation.
So what is it we need to be saved from? The answer is ourselves. Our hard and impenitent hearts that get between us and who God would have us to be. And the church-goer needs this every bit as much as anyone. It is because of this that we are storing up wrath for yourself on the day of wrath when God’s righteous judgment will be revealed.
When God's righteous judgment is revealed, what will that look like?
Here is what it won't look like: You, come on it because you followed the commandments, you attended church and gave a tithe of your income. You, come in because you stayed away from alcohol and drunks and people who sin.
Here is what it will look like: You, come on in because you gave me drink when I was thirsty. You fed me when I was hungry. You clothed me when I was naked. In all that you said, and in all that you did, you sought only to show your love for me. Enter into my kingdom.
God's kindness should lead us toward repentance. Toward a change. To where I no longer value the things that I valued, but now I value God, and in all I do, I show that to the world. So now, when I give a cup of water, it is not to earn God's favor (hand him a filthy rag), but it is because for me there is no other choice. I love others because of His great love for me. I serve others because of my great love for Him.