Once a person has sincere desire to do God’s will, that will is authenticated to him and he knows that it is the truth. He will have an instinctual awareness of this.
What about people who have never heard the Gospel? Is it fair for God to judge them? What about thousands and thousands of Hindus or people in Muslim lands? Would it be fair for God to judge them? Listen to these words of Christ. ‘If any man will do his will, he shall know of the doctrine.’ If there was anyone in the world, anywhere, at any time, in the most heathen, pagan darkness, who was willing to do God’s will, he would know of the doctrine. God would somehow communicate it. He would understand. He would know that the Christian message is the only authentic message. But the sad truth is there just is not anyone, anywhere, who of himself or herself wants to do God’s will. If there were, it would be well with them. If – but there is not. Not even the most privileged, the brothers, or half-brothers of Christ, who grew up in the same family; not even they believed in him. There has never been a person born and never will be until Christ comes again, anywhere in the world who of himself or herself desired to do God’s will. We are a rebellious human race. It always has to be a work of the Holy Spirit, God in his astonishing kindness cutting through all the resistance and the obstinacy, and opening up the heart to believe and to desire. It is always God’s initiative.