1 Timothy 2:3-4 For this is good and acceptable in the sight of God our Saviour; Who will have all men to be saved, and to come unto the knowledge of the truth.
If it's God's will for all men to be saved and come to a knowledge of Him, why don't they? How can God's will not be done?
Joh 10:26 but you do not believe because you are not among my sheep.
Joh 10:27 My sheep hear my voice, and I know them, and they follow me.
God has mercy upon certain people. Why is a complete and utter mystery because none of us deserves it. Christians only need to look around and ask themselves why Joe next door doesn't see God and they do? It's like the guards on the Damascus road who could see the light of God but ONLY Paul could hear the voice of God. If God wanted ALL men to be saved wouldn't that have been a perfect opportunity? Why could only Paul hear the voice?
While this view might seem harsh to some, Christians need to understand the implications. God is in total control. God will save those who He has mercy on according to His grace. All we do is abide in Christ being faithful to preaching the word and good works. We may see thousands saved or we may see no one. We don't need to be in a "numbers" game because God will draw all men to Himself-those that are His sheep. Whether we see anyone come to God through our preaching doesn't matter. God just wants us to be faithful to Him.