I am now knowledgeable in Judaism, Christianity (as a whole) and Islam.... kinda.
Judaism believes in one God who is never beginning or ending. His power is unfathomable. BUT, God is a singularity and isn't divided into three or amongst everything or everyone. On the subject of Jesus. The Jews believe that Jesus was just a rabbi gone rouge. His message was mixed up and in the ensuing centuries people took his message literally and mistook him for the Divine. After death, the Jews believe in heaven and hell but nothing really agrees on how EXACTLY to get there (Unlike the Catholic faiths where you follow specific rules).
Christianity says that the Jews were onto something. The old testament is true, but now Jesus adds another layer to monotheism. God is divided into three parts: God, Jesus, and the Holy Spirit. Now, Jesus tells us that God is loving and fills everyone with the Holy Spirit (which is one of God's parts). Essentially, God is in everyone human being but so is free will. Through life we must choose our actions carefully because we will be judged at the end of day. In the afterlife, we sit in purgatory and make up for our sins. Then we get to go to heaven. People who are truly not sorry for their sins will go to hell.
Islam says that the Jews were onto something then Jesus came as a prophet and then the Christians screwed up. Here, they believe that the Torah (the books of Adam and Abraham) were the beginning message from God. Then Jesus came as a one of many other prophets with another message from God. His message was misconstrued and people mistook him as being part of God. This was blasphemous and so God sent Mohammad. Mohammad wrote down messages from God during most of his adult life. Then he died. Now, Islam treats him like Christians treat Jesus. But, he is not God or a part of God. Muslims are just really, really, into him. To be a Muslim, you must only acknowledge that there is only one God and that Mohammad was his prophet. Then you must follow a moral code of conduct given to Mohammad that explains what is mandatory, accepted but not mandatory, not a good idea and what is band. THEN, you must mind the call to prayer 5 times a day, but only men must go to Church for the afternoon call to prayer on Fridays. THEN, you must make a pilgrimage to Mecca once in your life if you can afford it. But don't worry, if you can't afford it, you're OK. foreign to us. When you die, you go to heaven or hell but there is no purgatory for making up your sins.
How has my faith changed in learning all of this?
I am not Jewish and I am not Christian and I am not Muslim, mostly. I think the Torah is a book of prophets' experiences with God. Then they orally told people these stories for centuries and in the game of telephone, stories got out of hand. Then Jesus came about and the same thing happened with his stories. But, they weren't as outrageous since they were written down maybe 50 years+ after his death. But then figure in the translation from Aramaic to Greek to German to English and we might have changed a few words. Then Mohammad came along and he wrote his own story down (Thank God), but then most of his writing didn't include ALL of today's issues so for the last 1600 years Scholars and Scribes have been decoding and analyzing Mohammed's writings and trying to make them fit today's issues. Kinda like fitting a 1600 year old square wooden peg into a brand new titanium round hole.
If anything I have seen the flaws of modern religions. The biggest flaw is that these religions are based on other people's experiences. We have taken these experiences and made them so generic they have lost their holy flavor. I mean, Moses was given the Ten Commandments and the Talmud (oral commandments) and we just see these as options just because we "accept Jesus Christ as our lord and Savior?" That's not how it's supposed to happen. All religions have a basic code of conduct and morals. Every religion has a basic understanding that you should be nice, not kill or steal and help out your fellow man. So, why aren't we living this way? We are always scheming or angry with something. We don't know our neighbors. We don't volunteer or give to charity (other than when we annually clean out our closet). We don't have gatherings and celebrate unity in life. Instead, we're always angry with someone from work or someone who cut us off in traffic. We become hermits so we don't have to wave at the neighbor driving by. We keep that dollar at the grocery store because "I don't have Muscular Dystrophy." And on the weekends, we go out and get wasted so we can escape our hermit, self-loathing, pathetic lives. When we live like this, it's no wonder why people have forgotten reigion.
Here's the solution:
1.Be a good person. Say "hi" to your neighbor and maybe learn their name.
2. Start your own conversation with God. He might not speak loud enough at first, but be patient and listen harder.
3. Be nice to people you don't know. If someone speeds up next to you on the freeway and you know they are going to get in front of you, let them. You knew they were going to anyways. WHY are you upset about that 1/6 second gap?
4. Give a dollar at the grocery store or run a charity race or drop off canned goods at any catholic church or give a dollar to the homeless guy on the corner even if you don't believe he's homeless or buy some dog food for the kennel. Just do something more than giving out your nasty ass clothes that you, let alone anyone else with style, really wants.
5. Laugh. Meet up with friends and talk, gossip, and tell them that you love them. You don't have to spend money on a lavish dinner, maybe a pot-luck would do. Maybe a trip to the theater or a dog pound or just hang out.
6. Be nice to animals and the world around you. Have you ever looked into the eyes of a dog running around with you? They have pure joy and love for you! Now, have you ever stepped on a dog's foot when you didn't see them behind you? It's total pain but they still love you. The point is, every animal can feel emotion. Why not give them happiness? Eventually, your cold miniature heart will grow back and you will feel good for doing so. And, more than likely, you'll do good deeds and not realize it but on the flip side, you'll always feel good just from doing good deeds!
My afterlife: I don't know what to expect but if you are a good person, regardless of whether I believe that Jesus is part of a three part God or if I believe that Mohammad was a prophet, I'll go to heaven. Because God wants to love me, wants to love through me, and wants to be loved by me.
Side note on Islam. I like this religion (I don't understand the fantatical side of it). Think of them as the first Protestants who have their own prophet. I think the biggest hang up that the West has about Islam is that it's in a different language. I mean, Christianity has all traditional European names and you go to Europe to visit a holy place. Islam is so ethnic and you have to learn to pronounce these flemmy phrases and these names are so ... different.
But the reason why everyone in the Muslim world has the same name is because the first born has to be named after someone religious like Mohammad, Fatima, or Allah (Al-?). Simple as that.