We know for sure that, for a person to be a true Christian and to obtain salvation and eternal life, God the Father must call him: "No one can come to Me unless the Father who sent Me draws him; and I will raise him up at the last day" (John 6:44).
Also, God wants every single human being to eventually have an opportunity for salvation: "For this is good and acceptable in the sight of God our Savior; Who will have all men to be saved, and to come unto the knowledge of the truth" (I Timothy 2:3-4, emphasis ours throughout).
However, it is very obvious that many millions have not been called. Every day, many human beings—even innocent babies—die without having had the opportunity to know God or His way of life. So does this mean that God is cruel or capricious in His selectiveness? Are all of those millions are born merely to be "lost"—with no hope at all?
Not at all. The answer is that, although God certainly is selective, His selectiveness is based upon time. He is calling some people now and will call some later. The apostle Paul uses the phrase: "every man in his own order":
But now Christ is risen from the dead, and has become the firstfruits of those who have fallen asleep. For since by man came death, by Man also came the resurrection of the dead. For as in Adam all die, even so in Christ all shall be made alive. But each one in his own order: Christ the firstfruits, afterward those who are Christ's at His coming. Then comes the end, when He delivers the kingdom to God the Father, when He puts an end to all rule and all authority and power. (I Corinthians 15:20-24)
And I saw thrones, and they sat on them, and judgment was committed to them. Then I saw the souls of those who had been beheaded for their witness to Jesus and for the word of God, who had not worshiped the beast or his image, and had not received his mark on their foreheads or on their hands. And they lived and reigned with Christ for a thousand years. (But the rest of the dead did not live again until the thousand years were finished). This is the first resurrection [meaning it is not the only resurrection]. Blessed and holy is he who has part in the first resurrection. Over such the second death has no power, but they shall be priests of God and of Christ, and shall reign with Him a thousand years.
The author of Hebrews refers to "a better resurrection," probably referring to the first resurrection: "Women received their dead raised to life again: and others were tortured, not accepting deliverance; that they might obtain a better resurrection" (Hebrews 11:35) .
Back to the original question: Does God know in advance whether we will accept His calling? Can He look into the future to see what our decision will be?
From the example of Abraham, it appears that He does—or at least He can if He chooses to. We might think because after Abraham proved that he was even willing to obey God's command to sacrifice his son, God said, "Now I know that you fear God, since you have not withheld your son, your only son, from Me" (Genesis 22:12). But many years before this test, God was able to look into the future and to know the results of Abraham's obedience and many fine details of his life and those of his descendents. See Genesis 12:1-3, 7; 13:14-17; 15:1-21; 17:1-8, 15-21; 18:18-19.
From this, it appears that God can accurately predict whether or not a person will enter His Kingdom, and further, God works diligently and powerfully to bring those He calls to salvation. However, ultimately, the individual chooses to accept or reject Jesus Christ as his personal Savior because God does not strip those He calls of their free will. As God commands in Deuteronomy 30:19, "I call heaven and earth as witnesses today against you, that I have set before you life and death, blessing and cursing; therefore choose life, that both you and your descendants may live."