The most important verse in the Bible for unbelievers is John 3:16: “For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life.” The most important verse in the Bible for believers is 1 John 1:9: “If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.”
Once a believer has entered into eternal fellowship with God by believing in Christ (John 3:16), he soon realized that he still has the flesh (the old sin nature). So, he must maintain his temporal fellowship with God through regular confession of all known sins (1 John 1:9). Only then, through the fellowship and power of the Holy Spirit, can he produce divine good through the successful exercising of his spiritual gifts.
I learned this from Dr. John Danish. This is why I lovingly like to refer to this latter verse as 1 John Danish 1:9.