As I continue to lay out this argument about this religious tolerance that has taken hold of us Christians (and specifically, that it's more of a pagan thing than a God thing), one of the best places to start is simply to look at some of the fundamental differences between the gods of the various religions in our world and demonstrate that, no, they are not the same god with simply another name; they are vastly different gods.
There is much to love about the peace, the tranquility, and the centeredness of the Buddhist religion. Many of us look at our Buddhist neighbors and say, man, I wish my faith could be like that. I want my devotion to God to lead me to that kind of life. But it's no god that got Buddhists here; they have no god. In the Buddhist idea, all is god, and god is all, and the entire aim of life is to live peacefully and attain a transcendence whereby one becomes one with all. The devotion is led by those who have gone before who have attained this status, those who have succeeded and done it, who are not gods, but who are guides. The "gods" of Buddhism do not claim to be gods; this is vastly different from the Christian God, who boldly declares, "I Am the Lord." Additionally, the central idea of Buddhism is the emptying of oneself. For Christianity, the central idea is fullness - fullness of life, fullness of grace, fullness of Spirit.
Hinduism is known for its plethora of gods. For any wish, want, desire, or need you could possibly have, Hinduism has a god for that. There are a few principle deities, which tend to be worshiped by larger numbers of the faithful, but the sheer number of possible deities in this religion is staggering. The faithful know more about these gods than I can ever even pretend to, so I won't, but contrast this idea with the Christian God who is "One." He is "the way, the truth, and the life." He is everything. And He is "a jealous God." There is a fundamental difference between having a god for everything and having a God who is everything.
One of the popular ideas in the modern world is to say something like, "I'm spiritual, but not religious." This is true for a lot of people, and it should be - we are spiritual beings. (Someone once said we are spiritual beings on a human journey.) But what this does is acknowledge the hunger, the ache, the connectedness that the Spirit feels and longs for without having any real outlet for it. In the absence of a "religion," the spiritual have settled for the absence of a God, and this has left them without anything in this world bigger than themselves. They are eaten alive by the hunger that grows inside of them. Contrast this with the Christian God who breaks bread with His friends and feeds His faithful.
A stone's throw from the "spiritual, but not religious" crowd is the "religion" of humanism, which worships the self. There are a bunch of different manifestations of this, but it all boils down to the same thing - I am my own god. I decide what is right and wrong. I decide what works for me. I decide how I want to live, how I want to die, whether I want to love. The problem here is that when you are your own standard, there is no standard at all. When you let yourself down, you just change your expectation so that, hey, it's okay. When you do wrong, you just redefine wrong as right because, hey, it works for me. There's no inspiration, no inclination to do better because you're doing just fine. There is nothing in this world bigger than you and so nothing to hold yourself accountable to. You just are what you are. But the Christian God says you are what He created you to be. You're special not just because but because you are created in the image of God. Even in your very being, there is something bigger than you, something that inspires you to grow, to mature, to be better than you are today. And God creates not just you, but the standards, as well, so that there is no question what is right and wrong. No question what works or doesn't work. No question about how you ought to live, how you ought to die, how you ought to love. The Christian God provides a concrete way to live; the god of self is always trying to figure it out anew.
Things start to get a little more muddled when we come to the religions closest to Christianity. Islam, for example, actually does start in somewhat the same place - with Abraham. If you remember your Bible, Abraham had two sons - Ishmael with the servant Hagar and Isaac with the wife Sarah. Ishmael, the illegitimate child, was sent away after Isaac comes on the scene, and Islam is the religion of Ishmael. Often, this leads the uneducated to say that Allah and God are really the same god, just with a different name. But both Christians and Muslims would reject this idea. (For the record, the Muslim argument is that the Bible is corrupt and therefore cannot accurately convey the character/nature/reality of this God of ours.) Allah has no intimate relation with his people the way that the Christian God does. He holds out no promise of heaven; heaven must be earned. There is no grace. There is constant strife. And I think, fundamentally, this comes from the story of Ishmael vs. the story of Isaac - Allah never brought his people home. They're still wandering. They're still searching. They're still living the life of the cast-out. The Christian God creates a place for His people. He brings them home. He ends their wandering. He is found. And He welcomes in the outcast. So while it's tempting to say this must be the same god with just a different name, since both religions start with Abraham, it's not accurate. And the implication is the difference between living life as a wanderer and living life as a prodigal.
Finally, most closely related to the Christian God is the g-d of Judaism. (Jews do not utter the name of their g-d, which is why I have omitted the middle letter, per their custom.) This is super-muddled because they actually are the same deity, to some degree. The g-d of the Jews is the God of the Old Testament. We know the story of this g-d intimately, and we say, of course these are the same gods - we just have two versions of the story that end in different places. But that's what creates the dramatic difference here. The g-d of the Jews leaves them living under the law. He is a g-d who has made the promise, but has not delivered on it; they are still waiting on the Messiah (and some have even said that the time for the Messiah has passed, so he is not coming; others believe in Jesus as the Messiah, in addition to continuing the law-based religion of Judaism). For the Christian, God has both promised and delivered, and He has promised again, which is why we can have any hope at all in Heaven. He's already delivered on one promise, so we can trust Him to deliver on another. And we live not under the law, but under grace. Which means that even though Jews and Christians can legitimately claim to serve the same Lord, there are still fundamental differences here, as well, which have serious implications for both theology and for living.
So we say that whatever god a person serves is the same God with a different name, but it's just not the truth. There are fundamental differences at every juncture that set the Christian God apart from these others. (And it is true that it sets them apart from Him, as well.) Claiming anything else is either foolishness or ignorance. The Christian has a God who fills His people, who is One, who feeds His people, who holds them to a higher standard, who brings them home, who delivers on His promises, and who extends His grace. No other religion can say that. None.
There is something special about our God. And that's why we need to stop selling Him out in the name of religious tolerance.
Because God's people aren't supposed to be good at that; that's for the pagans.