This miracle [the new birth] all began with God: we were chosen by the Father (Eph. 1:3-4). This took place in the deep counsels of eternity, and we knew nothing about it until it was revealed to us in the Word of God. This election was not based on anything we had done, because we were not even on the scene. Nor was it based on anything God saw that we would be or do. God's election was based wholly on His grace and love. We cannot explain it (Rom. 11:33-36), but we can rejoice in it.
'Foreknowledge' does not suggest that God merely knew ahead of time that we would believe, and therefore He chose us. This would raise the question.'Who or what made us decide for Christ?' and would take our salvation completely out of God's hands. In the Bible, 'to foreknow' means 'to set on's love upon a person pr persons in a personal way.' It is used this way in Amos 3:2: 'You only have I known of all the families of the earth.' God set His electing love on the nation of Israel. Other verses that use 'know' in this special sense are 1 Corinthians 8:3, John 10:14, 27; Matthew 7:23; and Psalm 1:6.
But the plan of salvation includes more than the Father's electing love; it also includes the work of the Spirit in convicting the sinner and bringing him to faith in Christ. The best commentary on this is 2 Thessalonians 2:13-14. Also, the Son of God had to die on the cross for our sins, or there could be no salvation. We have been chosen by the Father, purchased by the Son, and set apart by the Spirit. It takes all three if there is to be a true experience of salvation.
I don't want to put words into his mouth, but I rather suspect that Dr Wiersbe (incidentally one of the most gracious men I have ever met) would not want the label 'Calvinist'. And there's no reason why he should; we don't contend for labels but for truth. Nonetheless, this extract from his little commentary on 1 Peter ('Be hopeful') shows his commitment to unconditional election, does more than hint at effectual calling and is consistent with definite redemption. Good on 'im!