Hi robert,
I believe scripture speaks plainly of two kinds of callings.
One is what you might refer to as the "outward call". It is when God uses preachers and evangelists and Christians to preach the gospel to every creature. God is commanding all men to repent, because all men are sinners. God's holiness requires him to command sinners to repent.
But the problem is, this outward call doesn't accomplish anything. Because all men are fallen and unregenerate by nature, haters of God, enemies of God, in rebellion to God, cannot understand the spiritual things of God, and find the gospel as foolishness.
Thus the only way anyone at all is saved is by what you might call the inward call. This is the call of God that actually comes to us and changes us. It makes us born again. It gives a new nature. It replaces the stony heart with the heart made of flesh (alive). It turns our will around so that we go from unwilling to willing. It removes the blindfold so that we can see Christ's beauty. It results in us seeing our sin for what it is and seeing that Christ is a worthy savior.
When this inward call happens, it results in salvation 100% of the time, every time. Obviously it doesn't happen to everyone because not everyone is saved. This is where the doctrine of election comes into play.
Eph 2:1-4 And you were dead in the trespasses and sins ...but God...made you alive...
Acts 16:14 The Lord opened [Lydia's] heart to pay attention to what was said by Paul.
Act 13:48 And when the Gentiles heard this, they began rejoicing and glorifying the word of the Lord, and as many as were appointed to eternal life believed.
Joh 6:65 And he said, "This is why I told you that no one can come to me unless it is granted him by the Father."
Joh 3:5-8
(5) Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God.
(6) That which is born of the flesh is flesh, and that which is born of the Spirit is spirit.
(7) Do not marvel that I said to you, 'You must be born again.'
(8) The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit."
Jas 1:18 Of his own will he brought us forth by the word of truth, that we should be a kind of firstfruits of his creatures.
Eph 2:8-10
(8) For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,
(9) not a result of works, so that no one may boast.
(10) For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
Eze 36:26 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh.
Eze 36:27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
1Co 1:22-24
(22) For Jews demand signs and Greeks seek wisdom,
(23) but we preach Christ crucified, a stumbling block to Jews and folly to Gentiles,
(24) but to those who are called, both Jews and Greeks, Christ the power of God and the wisdom of God.
1Co 2:7 But we impart a secret and hidden wisdom of God, which God decreed before the ages for our glory.
{Emphasis mine}
