As far as it compares to the holiness of God, all sin is the same. Every sin, from anger to murder, from white lies to adultery, will lead to eternal condemnation (James 4:17; Romans 6:23). All sin, no matter how “small,” goes against the nature and will of an infinite and eternal God and is therefore deserving of an infinite and eternal punishment (Isaiah 13:11). In this sense, there is no “worst” sin.
Not only does God hate sin because it goes against His will for us, but also because sin separates us from God (Isaiah 59:2; Jeremiah 5:25). God does not want us to be separated from Him. Thankfully, He has provided a way to “cleanse us from all unrighteousness” (1 John 1:8–10) through His Son, Jesus Christ (John 3:17). First Timothy 2:4 says that our Heavenly Father “desires all men to be saved and to come to the knowledge of the truth.” Your sin does not have to equal your condemnation—no matter how terrible you feel it is (see Romans 8:1).
Just as there is no sin too small to be worthy of punishment, there is no sin too “big” that God cannot forgive it. When a repentant prostitute came to Jesus, she found grace; Jesus then said to the onlookers, “I tell you, her sins—and they are many—have been forgiven” (Luke 7:47, NLT). Jesus died to pay the penalty for sin (John 3:16; 1 John 2:2). Second Corinthians 5:21 tells us that “God made [Jesus] who had no sin to be sin for us, so that in him we might become the righteousness of God.” For the believer, there is no sin Jesus’s sacrifice does not cover; there is no sin God cannot forgive, even if we consider it the “worst” (see 1 Timothy 1:15).
It is true that some sins will have bigger earthly consequences than others. Murder, for example, is going to have a much worse effect than harboring private hate. A chronic liar in a position of authority will have a wider negative effect than the child who fibs to his mother about stealing cookies before dinner. Sin is sin, but it can have different degrees of severity, and some sins call for worse penalties than others in this world.
As believers, we should hate sin as much as God does. We are “sons of the light and sons of the day. We do not belong to the night or to the darkness” (1 Thessalonians 5:5). God has set us apart as “a holy nation, a people belonging to God” (1 Peter 2:9). Holiness is not earned; rather, it is given by the Holy Spirit as He sanctifies us (2 Thessalonians 2:13; 1 Peter 1:15–16). Christians will still sin, but God promises to help us in the fight for righteousness (1 Corinthians 1:8).
Do not fall into the trap of comparing sins, judging others for “worse” sins than yours, or using the seeming triviality of one sin versus another as an excuse to do it. Your first concern should be your own sin—not the sin of those around you (Matthew 7:4–5). God’s standard is not how well you measure up to other people but how you measure up to Christ.
Each person’s sin is a reflection of what is in his heart (Matthew 12:34) and emerges through his thoughts, words, and actions. God judges all these aspects of our lives and will justly yet lovingly discipline His children when they sin (Proverbs 3:11–12; Hebrews 12:5–11). God’s discipline can take varying forms, depending on each person’s situation, to bring about repentance and renewal of fellowship with God. In the end, a believer who sins then experiences discipline will come out with a stronger faith, a renewed relationship with God, the wisdom of experience, and patience (James 1:2–4).
Is there a “worst” sin? Earthly consequences for various sins vary, but heaven’s perspective is different. First Corinthians 6:9–10 lists several sins that will keep a person from inheriting the kingdom of God. On that list are some sins that people like to rank as “worse” than others, yet Paul treats them all as equally damning. The same is true in Revelation 21:8, a list of sins that doom people to the lake of fire—lying is placed next to witchcraft and idolatry. All sin is equally bad in God’s eyes; the standard is the glorious perfection of His Son, and we all fall short of that (Romans 3:23). We need the righteousness of Christ, and, praise Him, that’s what He gives us when we believe (Romans 3:26; 4:5). In the final analysis, we might say that the “worst” sin is unbelief. To reject the Savior is to accept the penalty for one’s own sin. But no sin will condemn a born-again believer in Jesus Christ, because the penalty has already been paid (1 Peter 2:24).