You erroneously interpret all of those scriptures that you cited above to teach that man is saved by works. You could not make it any clearer that you teach salvation by works. Your argument about being saved by grace "after accomplishing a work that God commands you to do" sounds similar to what Mormonism teaches. In 2 Nephi 25:23 (from the book of Mormon) we read "..it is by grace that we are saved, after all WE can do." In other words, do all YOU can or else the Lord won't be able to save you, which is in complete contradiction to (Romans 4:5-6; Ephesians 2:8,9; Titus 3:5 2 Timothy 1:9 etc..) Your argument also reminds me of what someone who attends the church of Christ (Campbellism) once said to me during a discussion: "It is works of obedience that help to save us and not works of the law or works of merit." That is also in complete contradiction to (Romans 4:5-6; Ephesians 2:8,9; Titus 3:5 2 Timothy 1:9 etc..)
Noah had already "found grace" (Genesis 6:8), was "a preacher of righteousness" (2 Peter 2:5), and "walked with God" BEFORE he built the ark. His obedience was a DEMONSTRATION of his faith, not the origin of it and building the ark saved Noah and his family (physically) from drowning (Hebrews 11:17).
In regards to Naaman, if being healed from leprosy is an illustration of salvation by works (being immersed 7 times in the Jordan river) we have another case that reveals one can be saved without any water. *Read about it in (Luke 5:12-15). *No water is found here. Naaman was not even a believer until "after" dipping in Jordan. He said "NOW" (after being healed) I know that there is no God in all the earth, but in Israel," (2 Kings 5:15) and vowed to worship only Him (verse 17). If we follow this "example," we will have to baptize unbelievers! Naaman received cleansing from leprosy (not eternal life) after he dipped in the Jordan 7 times, but no sins were literally remitted for Naaman in Jordan. Likewise, water baptism does not literally remit sins. The NT uses the experience of Naaman as illustrative of the SOVEREIGNTY OF GOD, not of salvation by works/water baptism. Naaman was a heathen, not a believer, and did not know God until the miracle occurred. The purpose of the miracle had nothing to do with salvation by works, but was to demonstrate "there is a prophet in Israel" (2 Kings 5:8) and that "there is no God in all the earth, but in Israel," as Naaman found out (2 Kings 5:15).
Sadly, you seem to have more faith in water baptism to save you than you do in the death, burial and resurrection of Christ.Those who refuse to believe the gospel by trusting in the death, burial and resurrection of Christ as the ALL-sufficient means of their salvation (1 Corinthians 15:1-4; Romans 1:16) end up turning to supplements. In your case it's water baptism. *Yet Christ's finished work of redemption is sufficient and complete to save believers. *No supplements needed. (Romans 3:24-28)
Romans 5:1 - Therefore, having been justified by faith, (not faith and water baptism) we have peace with God through our Lord Jesus Christ. 2 - through whom also we have access by faith into this grace (not faith and water baptism) in which we stand, and rejoice in hope of the glory of God.
God's grace is unmerited and shows us mercy, kindness, and patience instead of the judgment that we deserve for sinning against Him. God's grace cannot be earned by our actions. Grace is based on the character of God and not on our works, performance, ability to keep the law etc.. Otherwise, grace would no longer be grace.
Romans 11:6 - "But if it is by grace, it is no longer on the basis of works, otherwise grace is no longer grace."
Ephesians 2:8,9 - We are saved by grace through faith, not works, not of ourselves it is the gift of God.
2 Timothy 1:9 - "who has saved us, and called us with a holy calling, not according to our works, but according to His own purpose and grace which was granted us in Christ Jesus from all eternity."
God's grace (enabling power) also operates sovereignly in the lives of believers.
1 Corinthians 15:10 - But by the grace of God I am what I am, and His grace toward me did not prove vain; but I labored even more than all of them, yet not I, but the grace of God with me.
2 Corinthians 1:12 - For our proud confidence is this: the testimony of our conscience, that in holiness and godly sincerity, not in fleshly wisdom but in the grace of God, we have conducted ourselves in the world, and especially toward you.
Titus 2:11 - For the grace of God that brings salvation has appeared to all men, 12 teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly in the present age.
Let's notice what (Rom. 6:3-18) teaches.
16. decide who to serve.
17. Obey a certain Doctrine (Rom. 6:3-6) (Acts 8:5,12,13, 26-40)
18. Being Then Freed From Sin ye became servants of righteousness. (Acts 22:16)
I think that about settle it.