Does Galatians 2 refer to the Jerusalem Council of Acts 15 or Paul's visit to Jerusalem in Acts 11?

One thing about the Bible that reminds us of God's glory and his perfect plan, is also something that can frustrate those of us who love details and trivia. The Bible is God's story. It only tells us about God and things that are relevant to him. So when we come to read a passage and we can't figure out what historical event it is referring to, we shouldn't take that as some kind of inaccuracy in the book, but a personal nudge that tells us we should probably be focusing more on the message that is being given to us.

Having said that... despite the overall unimportance of the detail of which visit to Jerusalem is described in 'Galatians 2'... figuring out details like this can be of use to us apologetically. In this case, figuring out which visit Paul writes about in Galatians can help us to put a date on when the letter was written, which in turn can give us confidence in how early the things he says were being taught in the Christian church, and go to disproving notions that the message changed over time. So it is with that in mind that I find this debate to have some value.

On to it then... Does Galatians 2 refer to the Jerusalem Council of Acts 15 or Paul's visit to Jerusalem in Acts 11?

What's the deal with speaking in tongues?

So you may be familiar with this Christian practice. It may also seem extremely strange for a group of people to be making sounds something like "Walla walla durka durka durka" and thinking that it's ok. You wouldn't be alone in thinking that. Even Paul the Apostle said:

If, therefore, the whole church comes together and all speak in tongues, and outsiders or unbelievers enter, will they not say that you are out of your minds? -- 1 Corinthians 14:23

But even for all the admitted weirdness, it is something that has a Biblical basis. '1 Corinthians 12-14' covers much of what tongues is about, but it also crops up elsewhere too.
The first time is in 'Acts 2' when the apostles gather for Pentecost. In verse 4 the Holy Spirit comes to them and allows them to speak in tongues. The following section details how there were Jews around from all over the world:

Parthians and Medes and Elamites and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabians—we hear them telling in our own tongues the mighty works of God. -- Acts 2:9-11

The people from these various nations could understand what the apostles were saying in their own languages.

And at this sound the multitude came together, and they were bewildered, because each one was hearing them speak in his own language. -- Acts 2:6

So, we see very clearly that in this instance, the gift of tongues was given so that the people around the apostles could clearly understand the Gospel message.
Then it goes on:

Does God Allow Us To Keep Slaves? (New Testament)

The slavery debate has been settled in our society for a good while now. We know it's wrong to take a person and keep them as property that we can do whatever we want with. Thankfully slavery is now illegal after a lot of hard fighting by people including Christians like Abraham Lincoln and William Wilberforce.

But some people think that the Bible allows or even commands us to keep slaves. If that's the case that seems to mean that God of the Bible is less than perfect morally. Fortunately for us, God, Jesus, and the Bible do not allow keeping slaves. So there's your short answer.

How about a slightly longer answer? Try these:

"There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus." Galatians 3:28

In Jesus' ideal world, all people are equally important. If everyone is meant to be equal, then slaves are a complete no-no.

"For we were all baptised by one Spirit so as to form one body--whether Jews or Gentiles, slave or free--and we were all given the one Spirit to drink." 1 Corinthians 12:13

Just to reiterate a point...
And finally, in case so far it sounds like the New Testament is OK with slavery because one day slaves won't exist any more, here's an Old Testament verse to put it all in perspective:

"Anyone who kidnaps and sells another person must be put to death. If they still have the person with them when they are caught, they must be put to death." Exodus 21:16

The trouble I think most people have with seeing passages in the Bible about slavery is that they read them through 21st century eyes. For most of us, our understanding of slavery is completely based on the image of black people being taken from their homes in Africa and forced into hard labour by rich white people. They were seen as property, no better than livestock, and had no respect or rights. They were considered sub-human. When we hear the word 'slave', we think of the worst type of slavery, because that's what we're familiar with. We can call this kind of slavery 'chattel slavery'. Sounds a bit like cattle, if it helps you remember. (The word 'chattel' is derived from 'cattle' anyway).
But the above verse from Exodus clearly says that taking someone and holding them as property to be sold is wrong. If that doesn't describe slavery as we know it, I don't know what does.

Is Christianity Based On Blind Faith?

Some people seem to have the impression that religious belief is always the same as 'belief without evidence'. They even seem to think that questioning a religious belief is supposed to be a sin, and the reason that so many people have faith is because they are scared that doing some research might send them to Hell.

It might be like that for some faiths... I don't know, I haven't checked them all... but Christianity is on very safe ground.