We have all been told that in one sense, sin is sin. All sin is a falling short of the glory of God. If we break one of the commandments, we have broken all of them because we have violated the law of God (Jas 2:10).

However, we also recognize that the consequences of certain sins are greater than others. In that sense, murder is worse than telling a lie.

But it is also true that sin can lead to other sins. Perhaps we could say that sin can grow into other sins (Jas 1:15). John speaks of this as walking in the darkness. When we sin, we are walking in darkness, and when we walk in darkness there is no telling how much we will stumble around, committing more sin (1 John 1:6; 2:9-11).

Peter is an example of this. We are all aware of how he denied the Lord three times. The Lord told him he would deny Him in this way, but in his pride and self-sufficiency Peter did not believe Him.

What is less obvious about the denials is that each one gets progressively worse. His denials become more emphatic. As Peter walked in darkness, he stumbled around more and more. There is a lesson there for all of us. Peter shows us what sin can lead to.

The first denial is the mildest of the three. It only involved one other person, and Peter simply wanted to extricate himself from the situation. A young lady came up to him and told him that he had been with Jesus (Mark 14:66-67). Peter told her that he did not know or understand what she was saying. He then walked away, hoping that was the end of the matter.

Mark, however, adds that when Peter walked away, a rooster crowed (v 68). This should have been a warning since the Lord told Peter that before the rooster crowed twice, Peter would deny the Lord three times (14:30). The sound of the rooster was a great time for Peter to reflect on what was happening. Instead, Peter was walking in darkness and did not see he was headed for even more darkness.

The second denial occurred later, after Peter had time to think. He was with a larger group of people, and in front of the group, the same young lady accused him of being one of Christ’s disciples. To deny Christ now involved doing so in front of many people. That is what he did. Mark says he denied Him again, but the verb for “deny” is in the imperfect tense. He said it over and over. Peter had to repeatedly deny the Lord as more and more people agreed with the assessment of the young lady. He could not simply walk away like he did with the first denial.

Once again, Peter had time to reflect on what he was doing after he had stated to a number of people that he was not a disciple of Jesus Christ. But eventually, those around him decided to ask him a third time. This also involved a number of people. Peter wanted to lay the matter to rest, so in very strong language he denied Christ. He placed a curse on himself if he were lying about it. He was asking God to curse him if he was a disciple of the Lord. His denial was emphatic. Not only did he proclaim he was not a disciple, but he also swore that he did not even know Jesus. This was worse than saying he didn’t know what they were talking about.

If we were to rate sins, this denial was certainly worse than the second. The second was worse than the first. When Peter heard the rooster for the second time, he came to his senses and understood what he had done. The words he had shouted to the people around him were still in his ears. He had gone from “I don’t know what you are talking about,” to “I don’t even know the Man!” He had gone from avoiding a single young woman to bringing down a curse upon himself in front of a crowd in his rush to distance himself from his Lord. His descent into darkness was quick and profound. There had been warnings, especially the word of the Lord. He had told Peter exactly what Peter would do.

Walking in sin is serious business in the life of the believer. It has nothing to do with losing or keeping eternal life. Once we have everlasting life, we have it forever. But if a believer walks in sin, he is walking in darkness. If we don’t listen carefully to God’s Word and seek to obey it, we will learn in our experience how dark that darkness can become. We are capable of doing what we think is unthinkable. Sin can grow quickly.