How to determine a genuine call from God?

Firstly, you need to understand that the way God dealt with people under the old testament (or old covenant) is very different to the new.

Many things that happened back then could not happen now. For example, judgement. God is not going to strike people dead under the new covenant.

Why? because ALL judgement has been given to the son

"For the Father judges no man, but has committed all judgment unto the Son" - John 5:22.

Jesus will one day return and Judge as is revealed in the book of Revelation. But, he hasn't come back yet. So until that time, you're not going to be struck down for making a mistake.

So looking at the character of Jesus (who represents the Father), how does he deal with people? He loves them.

Here is an example of the sort of thing that happened in the old testament, but with a very different outcome in the new.

54 And when his disciples James and John saw this, they said, Lord, will you that we command fire to come down from heaven, and consume them, even as Elijah did? 55 But he turned, and rebuked them, and said, You know not what manner of spirit you are of. 56 For the Son of man is not come to destroy men's lives, but to save them. And they went to another village. - Luke 9:54 - 56

I know some people will look at what happened in Acts 5:9 and say God judged Ananias and Sapphira and try to rebut what I'm saying here. But if you read acts 5 more carefully no where does it say that God struck them dead. And if what happened to them was God then you must ask yourself why God isn't killing Christians for lying. I would say it's because it wasn't God who killed them. If he was that harsh there wouldn't be any Christians to preach the Gospel and bring the good news! Neither would he say

"My little children, these things write I unto you, that you sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:" 1 John 1

God is not dealing with people like his was in the old testament. And the reason is because of Jesus. Jesus bore ALL of our sin at the cross. Now, people can be born again and made spiritually alive. They can be set free.

So if some guy in 2013 claims that God told him to kill his son, you know for sure that wasn't an instruction from God. God has not come to destroy men's lives but to save them.

I should further add that many of the events that occurred in the old testament were shadows (or images) of the Death/Burial and Resurrection of Jesus including Abraham being put to the test. Can you see it? It'll never happen again, we don't need another shadow when we have the reality in Jesus. :-)

The answer is really the same as for How does one discern between thoughts inspired by the Holy Spirit and those produced from themselves. Refer to that question for the full answer. In brief:

• Consult an experienced spiritual, see him/her regularly. He/She will attempt to discern with you whether following the alleged call would bring you into a deeper love for God [or the saints]. If so, the call is "provisionally accepted."
• Resist the call until your experienced spiritual advisor permits you to indulge. If it's a genuine call, not only will God leave a convincing message (with signs and everything), but He'll spam your number until you pick up.

To be clear, I'm not suggesting resistance to God. Always be eager to act on God's command. But, human fallibility requires a great deal of resistance to alleged calls to permit God's persistence and providence to outshine the trickery of our imagination -- not to mention that of the devil.

Refer to:

• Contemplation - Revelations and visions
• St. Ignatius's Discernment of the Spirits
• And "consolation" and "desolation"

Ryan has a good answer. But I want to expound on it a bit further. In Genesis 12:7 we see God promise the land to Abrahams offspring:

Genesis 12:7 The Lord appeared to Abram and said, “To your offspring[c] I will give this land.” So he built an altar there to the Lord, who had appeared to him.

So here we have a promise of God that the land will belong to Abrams offspring. But Abram questions this in Genesis 15:2-4

2 But Abram said, “Sovereign Lord, what can you give me since I remain childless and the one who will inherit[c] my estate is Eliezer of Damascus?” 3 And Abram said, “You have given me no children; so a servant in my household will be my heir.”

4 Then the word of the Lord came to him: “This man will not be your heir, but a son who is your own flesh and blood will be your heir.” 5 He took him outside and said, “Look up at the sky and count the stars—if indeed you can count them.” Then he said to him, “So shall your offspring[d] be.”

Here God reaffirms the covenant with Abram. Now after he is name Abraham he again questions the covenant, because he still has no son from Sarah. Again in Genesis 17:17 Abraham questions it:

17 Abraham fell facedown; he laughed and said to himself, “Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety?” 18 And Abraham said to God, “If only Ishmael might live under your blessing!

God again assures him of the covenant and that Sarah will bear a child for him.

Soon after Abraham begins to see that all that God has said would happen has happened. He starts to trust in God because God does what he says he is going to do. The test comes when God tells Abraham to go and sacrifice his son. If God allows this to occur then the promise of God will be nullified. If you have read the Bible it is clear that God always keeps his promises.

Abraham complies, because he knows that God will not allow the sacrifice to be completed. This is evident when he tells his son that “God himself will provide the lamb for the burnt offering”. Most people I have talked to about this seem to believe he is speaking of Isaac, but he is not. Abraham has gone from a man that was unsure of Gods promises to a man that now boldly believes in what God has promised him.

So much so that he is willing to raise the knife, knowing that God will stop him and provide for the sacrifice, and God does just that. Isaac also was very confident in God's promise as there is no evidence that he struggled with his father and allowed himself to be bound on the altar.

Is it moral for him sacrifice his child because of this experience? Isaac was never in danger of being sacrificed.

We have Scripture by which we can test these revelations.

“The prophet who has a dream, let him tell a dream;
And he who has My word, let him speak My word faithfully.
What is the chaff to the wheat?” says the Lord.
“Is not My word like a fire?” says the Lord,
“And like a hammer that breaks the rock in pieces?
(Jeremiah 23:28-29)

God calls people within the context of His revelation. If a person tells me out of the blue that God told him this and that, I have no reason to believe him; but if this call came from a context of God showing His presence and power, I need to look more closely.

Since the question refers to Abraham's willingness to sacrifice his son, lets look at the context of that command:

• God guided him from his homeland to the place promised to his descendants (Genesis 12)
• God promised him a son, though Abraham and Sarah were too old (Genesis 17)
• The Lord appeared to Abraham, and Sarah also saw and heard Him (Genesis 18)
• The destruction of Sodom and preservation of Abraham's nephew Lot (Genesis 19)
• God preserves Sarah from being violated as a result of Abraham's lie (Genesis 20)
• A nonbeliever converses with God in a dream concerning Abraham and Sarah (Genesis 20)
• Sarah has a son! (Genesis 21)

All of this comes before God tells him to sacrifice his son. God has proven himself to Abraham; Abraham obeyed because he trusted God.

It's much the same way with Jesus -- if you walk up to me and tell me that you are the son of God, I'm not going to believe you -- without anything in your life to support the claim, how can I believe it? But the context of Jesus' life makes it possible (even probable). God reveals Himself, then wants us to trust Him. He doesn't normally demand obedience without showing Himself to be trustworthy (though He does have every right to do so).