What is the difference between Baptists and Assemblies of God?
I attend a branch of the Assembly of God and have my whole life. The thing with baptist is there are different branches and they vary. Some baptist believe in once saved always saved. Which means, that once you are saved you can do anything you want to and you can make it to heaven still. Also, I think most baptist don't believe speaking in tongues. Some baptist think that you have to be baptized to make it to heaven. Whereas, Assembly of God is more stricter. Once you are saved you have change and be more like God. If you sin you ask for forgiveness. But just because you are saved once doesn't mean that you will make it too heaven. At my church there are people who speak in tongues. It is a message from God in a different language and interpreted by someone else. No one knows the language usually and God tell people what to say. We also think you don't have to be baptized to go to heaven. Being baptized is a something that you need to show that God is working in your life but it isn't necessary. I am sure there are other differences but those are the big ones that stick out in my mind.
I am a Biblical Studies student at a Baptist University. I would like for it to be noted that the term "once saved always saved" is in reverence to Romans 8:35-38. The question is sometimes asked, "So what if someone kills someone, are they still saved?" The answer most baptist would provide is that the person probably did not have a conversion/faith experience in the first place. Now we are not to judge the person, so we really cannot say whether they were a Christian or not. But like it says in Romans, nothing can separate us from the Love of God.
As far as baptism, we believe much the same. Baptism is a public profession of faith. It's sort of like a wedding ceremony. Now you can be married by just signing the legal paperwork, but most have a ceremony to show their commitment to their friends and loved ones. You can be a Child of God without baptism, but it is recommended to show your commitment as well.
The term baptist originally came from the term anabaptist which was a condescending term at the time of the reformation. Basically we split from the Catholics and sprouting protestants because we believed that infant baptism did not save a person and that the only thing that did was a profession of faith. The first baptist were among some of the most persecuted groups, and when they were caught they were tortured and often killed by binding them and throwing them in the river...or "baptizing" them. Their killers thought it would be a funny twist of fate.
The main difference in Baptist and Assembly of God is the gift of speaking in tongues as mentioned in 1 Corinthians 14. Unlike the previous paragraphs this issue in my opinion, is not to be divided over. I have never experienced this gift, however, I believe if it brings people closer to God then more power to them!
The main thing to remember about different denominations is that we all boil down to the same fundamental truths. That we as humans are sinners from birth, and since we are so we cannot be in Heaven because God is perfect and cannot be around those who are not. Therefore Christ came to earth as man and God to die for our sins and bridge the gap between man and God. By believing in Him we now have eternal life. John 3:16, Romans 6:23, Romans 3:23, Ephesians 2:8-9, John 14:6 and many others.
Some additional observations
I am a Bible believing sinner saved by the grace of God through the shed blood of the Lord Jesus Christ. I belong to an independent, fundamental Baptist church.
A personal friend of mine who is an Assembly of God pastor told me once that doctrinally our respective churches have many more similarities than differences. I agree with him; however, in the matter of the "sign" gifts (speaking in tongues, healing, and others) the difference is significant. Traditional, more conservative Baptists hold that these gifts, which were active during the time of the Apostles in the Book of Acts, ceased upon the completion of the written Word of God (I Cor. 13:8-10). Prior to that, the gifts were necessary in order to validate the teachings and preachings of the apostles during a religiously tumultuous time of spiritual transition in God's dealings with men, absent of the yet-to-be-completed canon of Scripture.
Assemblies of God, and even some more moderate and liberal Baptist churches, hold that the sign gifts are, or may be, active still today. While conservative Baptists would strongly disagree, some "non-cessationists" would even assert that true salvation is evidenced by a believer's possession of one or more of the gifts.