The way of God even before Adam and Eve sinned was obtaining eternal life by good works. Everlasting life was not free for them, so it cannot be free for anyone else. God created humans to do good works, which He had prepared beforehand so that they would walk in them. (Ephesians 2:10) He also created humans would be holy and blameless before Him. (Ephesians 1:4) The wages of the righteous is life. (Proverbs 10:16, Romans 6:23) He who is steadfast in righteousness will attain life. (Proverbs 11:19) In other words, in the way of righteousness is life, and in its pathway, there is no death. (Proverbs 12:28) All unrighteousness is sin. (1 John 3:4: 5:17, James 4:17) Therefore, the requirements for obtaining everlasting life for Adam and Eve were for them to be righteous, holy, and blameless before God.
It is clear that Adam and Eve lived with the hope of obtaining eternal life by good works, which the Lord, who cannot lie, promised them. (Titus 1:2) They understood four things their children today need to understand. First, that there is sin leading to death and sin not leading to death. Second, that if anyone sees his brother sinning not unto death, they shall ask and God will for them give life to those who sin not unto death. Third, that all unrighteousness is sin. (1 John 5:16-17) Fourth, that the way of the Lord is doing righteousness. (Genesis 18:19) Therefore, in the way of righteousness is life, and in its pathway, there is no death. (Proverbs 12:28) The Bible indicates that the Ten Commandments, and laws, and requirements of God predate sin. (Deuteronomy 4:13, Psalm 119:1, Psalm 119:80, Proverbs 28:18, Ezekiel 28:15, Luke 1:6, 2 Peter 2:21)
Even after Adam and Eve committed sin unto death, obtaining eternal life by good works continued. An important fact needs to be understood at this point. That fact is that there is not a righteous person on earth who continually does good and who never sins. (Ecclesiastes 7:20) Therefore, 100% obedience to the Lord is not required for everlasting life. Being righteous and holy and blameless before God simply means not being worthy of death. Consider the following three scriptures. (1) If someone sins worthy of death, they are put to death. (Deuteronomy 21:22) (2) There may be no sin in the person worthy of death. (Deuteronomy 22:26) (3) Those who practice such things are worthy of death. (Romans 1:28-32) Remember the wages of sin is eternal death; likewise, the wages of the righteous is everlasting life. (Proverbs 10:16, Romans 6:23)
It seems that from Adam to Moses, people have been obtaining eternal life by good works. Christ says, “I say to you that many will come from east and west, and recline at the table with Abraham, Isaac, and Jacob in the kingdom of heaven.” (Matthew 8:11) Moreover, He says, “In that place, there will be weeping and gnashing of teeth when you see Abraham and Isaac and Jacob and all the prophets in the kingdom of Heaven, but yourselves being thrown out.” (Luke 13:28) Do you not know that the unrighteous cannot inherit the kingdom of Heaven? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, will inherit the kingdom of Heaven. (1 Corinthians 6:9-10) Therefore, as most people believe, obtaining everlasting life by good works was present from Adam to Moses.
Under the Old Covenant
It is self-evident that even under the Old Covenant, obtaining eternal life by good works continued. God gave good laws that lead to everlasting life. (Leviticus 18:4-5; Deuteronomy 30:6-20; Nehemiah 9:29; Proverbs 4:1-9; Proverbs 7:1-3; Ezekiel 3:21; 18: 17, 19, 21-22, 27-28; 20:11, 13, 21; 33:15-16, 19) Ezekiel 18:27-28 even says that if you follow the way of righteousness you will save your life; you shall surely live; you shall not die. Therefore, the requirements for everlasting life are present under the Old Covenant. God also gave some laws that were not good for eternal life. (Ezekiel 20:25) These not good laws are contained in the book of the law, commonly called the Law. The not good laws were added because of transgressions under the Old Covenant, until the seed would come to whom the promise had been made. (Galatians 3:19) In other words, the Law was a penal code.
It is easy to see that these laws were not made for obtaining eternal life by good works. These laws were a tutor to lead people to Christ. However, since Christ has come, we are no longer under a tutor. (Galatians 3:23-25) They were weak and useless. (Hebrews 7:18) They related only to food and drink and various washings, and regulations for the body imposed until a time of reformation. (Hebrews 9:9-10) Therefore, we have been released from the Law. (Romans 7:6) Christ set us free from the law of sin and of death. (Romans 8:2) He canceled out the certificate of debt consisting of decrees against us, which was hostile to us; and He took it out of the way, having nailed it to the cross. (Colossians 2:14) All of the Apostle Paul’s negative comments about the Law are about the penal code in the book of the law.
Under the New Covenant
It is self-evident that even under the New Covenant, obtaining eternal life by good works continued. We know this because God does not change. (Malachi 3:6) Also, He does not change His spoken words. (Psalm 89:34) Also, He does not change His counsel for humans. (Hebrews 6:17) Moreover, He does not change His calling for humans. (Romans 11:29) Are we not called to be holy and blameless before God? (Ephesians 1:4) For those who disagree, let us look at some of the Old Testament precepts continued in the New Testament.
It is clear that doing the will of God relates to obtaining eternal life by good works. Those who do the will of the Lord who is in heaven will enter. (Matthew 7:21-23) You need endurance, so that when you have done the will of the Lord, you may receive the promise of everlasting life. (Hebrews 10:36) Live the rest of your time in the flesh for the will of the Lord. (1 Peter 4:2) Those who suffer according to the will of God entrust their souls to Him by doing what is right. (1 Peter 4:19) The will of God is that humans do what is right in His sight. (1 Peter 2:15) Whoever does the will of the Lord will live forever. Everyone who practices righteousness is born of God. (1 John 2:17, 29)
It is also clear that doing righteousness relates to obtaining eternal life by good works. Do not go on presenting the members of your body to sin as instruments of unrighteousness but present yourselves to God as those alive from the dead and your members as instruments of righteousness to the Lord. (Romans 6:13) When freed from sin, become slaves of righteousness. (Romans 6:18) Present your members as slaves to righteousness, resulting in sanctification. (Romans 6:19) Pursue righteousness, godliness, faith, love, perseverance, and gentleness. (1 Timothy 6:11) Pursue righteousness, faith, love, and peace. (2 Timothy 2:22) Live sensibly, righteously and godly in the present age. (Titus 2:11-12) Die to sin and live to righteousness. (1 Peter 2:24)
Furthermore, sinning (lawlessness) does not relate to obtaining eternal life by good works. A person is justified by good works and not by faith alone. (James 2:24) Everyone who practices sin also practices lawlessness, and sin is lawlessness. Whoever practices righteousness is righteous, just as the Lord is righteous. The one who practices sin is of the devil. (1 John 3:4, 7-8) Whoever is born of God does not practice sin. No one who does not practice righteousness is of the Lord. (1 John 3:9-10) Let the one who is righteous, still practice righteousness; and the one who is holy, still keep themselves holy.” (Revelation 22:11)
Moreover, being holy and blameless clearly relates to obtaining eternal life by good works. Those who endure to the end will be saved. (Matthew 10:22, 24:13, Mark 13:13) Work for the food, which endures to everlasting life. (John 6:27) They know the ordinance of God that those who practice such things are worthy of death. (Romans 1:32) The doers of the requirements of the Law will be justified. (Romans 2:13) Those who practice such things will not inherit the kingdom of God. (Galatians 5:21) God chose us from the beginning that we would be holy and blameless. (Ephesians 1:4) We were created for good works, which God prepared beforehand for us to walk in them. (Ephesians 2:10) Walk in a manner worthy of the Lord, bearing fruit in every good work. (Colossians 1:10) God will give everlasting life to those who sin not leading to death. (1 John 5:16)
Christ, who is the New Covenant, answered whether obtaining eternal life by good works applies under the New Covenant. He said that if someone wants to enter into everlasting life they should follow the way of righteousness. (Matthew 19:17, Luke 10:25) In other words, the conclusion, when all has been heard, is fear God and keep the way of righteousness, because this applies to every person. (Ecclesiastes 12:13)