In John 14:6 says, “I am the way, the truth, and the life, no one comes to the Father except through me.” Then in Acts 4:12 Peter said, “And there is salvation in no one else; for there is no other name under heaven that has been given among men, by which we must be saved.” This is plain, there is only one way of salvation.
It is for this reason, the need of sharing the gospel, that Paul said what he did in Romans 10:8-15 and particularly in vss. 14-15.
8 But what does it say? “The word is near you, in your mouth and in your heart”—that is, the word of faith which we are preaching, 9 that if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you shall be saved; 10 for with the heart man believes, resulting in righteousness, and with the mouth he confesses, resulting in salvation. 11 For the Scripture says, “Whoever believes in Him will not be disappointed.” 12 For there is no distinction between Jew and Greek; for the same Lord is Lord of all, abounding in riches for all who call upon Him; 13 for “Whoever will call upon the name of the Lord will be saved.” 14 How then shall they call upon Him in whom they have not believed? And how shall they believe in Him whom they have not heard? And how shall they hear without a preacher? 15 And how shall they preach unless they are sent? Just as it is written, “How beautiful are the feet of those who bring glad tidings of good things!”
This is why evangelism is such an awesome responsibility for us. But note another principle that we see in Romans 1:18ff.
18 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, 19 because that which is known about God is evident within them; for God made it evident to them. 20 For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. 21 For even though they knew God, they did not honor Him as God, or give thanks; but they became futile in their speculations, and their foolish heart was darkened. 22 Professing to be wise, they became fools, 23 and exchanged the glory of the incorruptible God for an image in the form of corruptible man and of birds and four-footed animals and crawling creatures. (emphasis mine)
Creation provides a clear revelation not only of the fact of God, but of His divine nature, and man’s refusal to recognize this is simply a matter of the hardness and rebellion of his heart. If someone wants to know God, He will get someone to them with the gospel. Missionaries have reported that they’ve found natives in villages who believed that there was one Supreme Being even though they were worshipping idols and demonic powers and were longing to know the true God. See also Acts 17:22-31.
Of course, Satan seeks to blind the minds of people so they will not respond to the light they have either in creation or in the gospel. In this he uses all sorts of tricks, deceptions, and hindrances. Some people use this as an excuse to reject the light they have, but interestingly, others still come to faith in Christ, regardless. While such negative conditions do make responding to Christ more difficult, it is not impossible and people are still without excuse. Also, the Bible teaches us that God is seeking to bring men to repentance and convict them of their need of God and Christ (see Rom. 2:4; John 1:9).