Are some sins worse than other sins? Does the Bible say that all sins are equal or that some sins are far worse than others?
What is Sin?
Sin is what is defined as breaking God’s laws. To sin is to commit cosmic treason against the King of the Universe. Sin is closely associated with what we call “missing the mark,” Is it like an archer whose arrow falls far short of a bull’s eye. Hitting the bull’s eye would be perfect obedience to God’s commands. The fact is that we all fall short  of God’s standard (Rom 3:23) and there is no one that is without sin (Rom 3:10; 1 John 1:8, 10). Only Jesus Christ the God-Man committed no sin. Sin can be said to be in violation of one’s own conscience, but more than that, it is a deliberate attitude, thought, or action that someone knows is wrong. Sin can also be acts of omission. Biblically speaking, sin is the transgression of the law of God (1 John 3:4).
Sins of Omission
There are sins of commission like stealing, lying, and cheating but there are also sins of omission. That is, when someone knows that they ought to do something and don’t do it, to them it is sin. James 4:7 says as much: “whoever knows the right thing to do and fails to do it, for him it is sin.” Even the unsaved are guilty of not giving God what is due Him, which is to give thanks for what He has done. What is the result of this? Romans 1:21 says that even though they “knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened.” For Christians, John tells them that “if anyone has the world’s goods and sees his brother in need, yet closes his heart against him, how does God’s love abide in him” (1 John 3:17)? These are sins of omission. That does not excuse them in anyway because sins of omission are still sins and that is missing the mark of God’s holy standard.
Sins of Commission
Sinning deliberately and willfully is obvious even to the unsaved (Rom 1). These sins include “all manner of unrighteousness, evil, covetousness, malice. They are full of envy, murder, strife, deceit, maliciousness. They are gossips, slanderers, haters of God, insolent, haughty, boastful, inventors of evil, disobedient to parents, foolish, faithless, heartless, ruthless. Though they know God’s righteous decree that those who practice such things deserve to die, they not only do them but give approval to those who practice them.” (Rom 1:29-32). Both Christians and non-believers will be held accountable for their sins of commission but at least the saved know that they will not be judged and condemned like the lost will (Rev 20:11-15) but they will suffer consequences because God, as a loving Father, disciplines every child of His ( Heb 12:5-6).
Are Some Sins Worse than Others?
Jesus said that if someone looks with lust at another they have already committed adultery or sexual immorality in their heart (5:28) but most certainly committing fornication or adultery is worse than just thinking about it because “Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body” (1 Cor 6:18) because anyone who is “joined to a prostitute becomes one body with her [or him]? For, as it is written, “The two will become one flesh” (1 Cor 6:16). The fact is that lying is wrong, so is stealing, and certainly cheating is but committing adultery is worse than lusting in the heart. Jesus also stated that hating someone is like murdering them in their heart (Matt 5:21-22) but He did not say that hating them is actually the same as murdering them, just as He didn’t directly say that lusting is just as bad as committing the actual act of adultery or fornication. Lusting and hating can lead to adultery and murder, but thinking about it and doing it are two different things altogether.
Not all sins are equal. I can lie to my wife and be sinning but to commit adultery is far more serious and has far greater consequences. Read what Jesus said about differences in responsibility in Luke 12:37-38 “that servant who knew his master’s will but did not get ready or act according to his will, will receive a severe beating. But the one who did not know, and did what deserved a beating, will receive a light beating. Everyone to whom much was given, of him much will be required, and from him to whom they entrusted much, they will demand the more.” Is there greater and lesser sins? Jesus told Pontius Pilate that “he who delivered me over to you has the greater sin” (John 19:11). Jesus was saying that Pilate was less responsible than were the Jewish leaders, and even though both were responsible, it was the Jews who brought Him to Pilate. Pilate also wanted to scourge Him and then release Him but the Jews demanded He be put to death by crucifixion. Another reason that the Jews were more responsible is because they knew that Jesus was from God (John 3) and they had seen His miracles, making the blind to see, the lame to walk, and He even raised the dead so they were without excuse.
Even if you have lived a good life, it only takes one tiny, little sin to send someone to hell. All sin is serious to God and is an affront to His holiness. We are told to be holy just as He is holy (1 Peter 1:16). That presents a problem because we are all sinners and we all fall short of His glory so how can we become holy just as He is holy? We need to repent (Luke 13:3, 5; Rom 10:9-13) and confess our sins (1 John 1:9) and trust in the Savior and only then will God the Father see us as having Jesus’ own righteousness (2 Cor 5:21). Unless we are seen as holy, we will never inherit the Kingdom and God (1 Cor 6:8-11) and our righteousness must exceed that of the Pharisees (Matt 5:20). Again, that seems humanly impossible, but for God, is anything too hard? The answer is no. If a person repents, confesses their sins, pleads to God for forgiveness, and then puts their trust in the Savior, they will be saved. There is no other way possible (Acts 4:12). He is the One and Only Way to heaven (John 6:44). That is where you are headed if you have repented and trusted in the Savior. Sins can be forgiven but it is only through and by the precious blood of the Lamb of God because being sorry is not enough…without the shedding of His blood, there can be no forgiveness  of sins (Heb 9:22). Only in this way can you be made whiter than snow (Psalm 51:7).
Related reading: What is the Original Sin? 
Resource – Scripture quotations are from The Holy Bible, English Standard Version® (ESV®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved.