So how do you know your faith is not a delusion? Other religions can claim that your God is evil in disguise. I think I have read somewhere that Gnostic Christians consider Yahweh Demiurge.
When you realize that all religion that is outside that which is prescribed by the Creator is from his adversary, you have to have in mind the criteria that is set forth in the scriptures to identify God's true worshippers.
Jesus is recognized as a great prophet in two of the Abrahamic faiths. So the way to determine who is really a follower of Christ and who is merely rendering lip service to his commands is in their actions and what kind of people they produce.
Islam is in the news a lot lately because of the activities of Muslim extremists in Iraq. We see no love expressed for anyone in their hate filled agenda. Converting at the point of a sword (or gun) is not the kind of service God requires. Their scriptures also fuel this violence because it is carried out to a fanatical degree and no god is served by their actions, except a tyrannical despot. The Creator is nothing like that. Not all Muslims reflect that hate but all are taught intolerance of infidels and if commanded to do so by their leaders, will kill them with little regard for their humanity.
Mere performance is not what God requires. We must love him with all our heart and imitate his son, (who was a perfect reflection of his Father) Jesus was a peaceful preacher of good news. He taught by word and deed what it means to love God and neighbor. Look for those who act like Christ.
Another example is Judaism....Jesus said we must "love our enemies". Do we find such love among any of those who claim to worship the God of the Bible?
The Jews have never really known an absence of war. They are like the rest of the world when it comes to bloodshed. But they reject Jesus.
Murdering the prophets God sent to correct them has been a pattern of their behavior down through history. By murdering the Messiah, they proved themselves unworthy of Jehovah's acceptance as his people, so after giving his nation one last opportunity to redeem themselves, he abandoned them as his people. (Matt 23:37-39) Their history proves that their God is not listening to their prayers.
God told his ancient people.....
Even though you make many prayers, I am not listening; with bloodshed your very hands have become filled. (Isaiah 1:15)
This holds true for Christians too. This is why we cannot confuse "Christianity" with "Christendom". (i.e. those who claim to be Christians but whose actions deny Christ's teachings) Has Christendom proved that she loves her enemies....or is she there supporting the wars of her respective nations? Aren't her hands also "filled with blood"? In her support for her country is she even guilty of participating in the murder of her own brothers? (1 John 4:20, 21)
Jesus said we would recognize his true disciples "by their fruits"....their works.
Just in that one teaching of Jesus alone, it is easy to see that those who spill blood are not acceptable to God no matter what they call themselves. Label wearers are of no value to God if their heart is not in his worship. The one thing God requires as an important part of our worship is obedience. He has no time for people who want to use scripture to justify their own abhorrent behavior.
It's kind of hard to verify which faith has the right God. So I assume that it doesn't matter to God how He is approached. But I could be wrong too. Even if I were a Christian I would assume that Jehovah doesn't mind if a Hindu worshipped Durga, because the Hindu is worshipping Him ultimately, although unknowingly. Your God doesn't really hate sinners so He wouldn't mind a non-Christian that much
On the contrary....it matters a great deal how and whom we worship. The God of the Bible does not tolerate the worship of false gods because it actually renders worship to the devil who masquerades as any god you wish, as long as it isn't Jehovah. By means of false worship, the devil siphons off worship for himself. It is all he has ever wanted, but not many would worship him for what he is. If he didn't masquerade as "an angel of light" only dark, sadistic people would have anything to do with him.
There are just two tables from which to "feed" ourselves spiritually...so we must choose carefully because.....
"....I say that what the nations sacrifice, they sacrifice to demons and not to God; and I do not want you to become sharers with the demons. You cannot be drinking the cup of Jehovah and the cup of demons; you cannot be partaking of the table of Jehovah and the table of demons. (1 Corinthians 10:16-21)
You can see that this is a serious matter.
The first of the Ten Commandments was to have 'no other gods but Jehovah'. There was to be no idolatry and no bowing to false deities. False religion is rife with idols and false gods, so unless a person abandons false worship and adopts the worship of the one Jesus called "the only true God" (John 17:3) then they are on the wrong road.
God will lead right hearted ones to the truth, (John 6:44) but those who want to do things their way will be permitted to continue in the delusion created by the devil. It is what their heart desires so God let's them have what they want. (2 Thess 2:9-12)
There is one truth and one God.....our heart must seek him out and we must align ourselves with his people if we want to earn his favor.
"Search for Jehovah, you people, while he may be found. Call to him while he proves to be near. (Isaiah 55:6)