Because all religions, including most Christian denominations, are based upon avoiding sin and doing good works in order to get to heaven, most evangelicals have totally focused their preaching on God's grace. Perhaps the most often used passage of Scripture for those interested in winning souls for Christ, is no longer John 3:16, but is Ephesians 2:8-9, which practically defines "grace" by itself; it says: "For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: not of works, lest any man should boast."
While this passage from Ephesians is critical when one is addressing a person who is mistakenly relying upon a works-based religion, it, in itself, is not capable of bringing the lost to salvation. Romans 1:16 states that it is the Gospel message that has the power necessary to bring someone to Christ; it reads: "For I am not ashamed of the Gospel of Christ: for it is the power of God unto salvation to everyone that believeth; to the Jew first, and also to the Greek."
So, what exactly is the Gospel? The Apostle Paul defined it as being composed of three historical facts as seen in 1 Corinthians 15:3-4:
1. Jesus died for our sins according to the Scriptures. Because all are guilty of sin, and because the judgment of God is that sin must be paid for by death (Rom. 3:23; 6:23; etc.), man has two choices - he can pay for his sin with his own death, or he can accept the One Who volunteered to pay that death for him (Rom. 5:8)
2. Jesus' body was placed in a borrowed tomb; He was buried (Mt. 27:57-61; Mk. 15:42-47; Lk. 23:50-56; Jn. 19:38-42). In addition, His body was guarded so that no one could steal it and claim He had risen (Mt. 27:62-66; 28:11-15)!
3. Jesus rose again from the grave three days later as the Scriptures had promised (Ps. 16:10; Mt. 12:38-40; Acts 2:27; 13:35; Mt. 28:1-10; Mk. 16:1-11; Lk. 24:1-12; Jn. 20:1-18; etc.)!
It is by faith in Christ's death, burial, and resurrection for us, that results in salvation. But, salvation is not the end of our relationship to Christ, but the beginning. We are saved to live for Him, to obey Him as Lord. The Ephesians 2:8-9 passage is immediately followed by verse ten which says: "For we are His workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them." We have been saved, true, but we are also commissioned to share the Gospel with others (Mt. 28:19-20; Acts 1:8; etc.)! We serve our Lord as His ambassadors on earth (2 Cor. 5:20). We are the Lord's "hands and feet" (Mt. 25:31-46)! And, out of gratitude, we not only make every effort to avoid sinning, but more than that, to avoid even the appearance of sinning (1 Thes. 5:22)!