Out of Context
It is quite common for people to quote from the Bible "out of context".
Consider the verse below for example.
That ye may eat the flesh of kings, and the flesh of captains, and the flesh of mighty men, and the flesh of horses, and of them that sit on them, and the flesh of all men, both free and bond, both small and great.
- Revelation 19:18 (KJV)
People use that verse to say that Christians are cannibals. Which obviously they're not.
But then if you look into the context (in this case the verse above it) things change a bit.
And I saw an angel standing in the sun; and he cried with a loud voice, saying to all the fowls that fly in the midst of heaven, Come and gather yourselves together unto the supper of the great God; That ye may eat the flesh of kings, and the flesh of captains, and the flesh of mighty men, and the flesh of horses, and of them that sit on them, and the flesh of all men, both free and bond, both small and great.
- Revelation 19:17-18 (KJV)
So now we see that it's the birds that eat the flesh. That changes things completely.
Sometimes you have to read the entire chapter to understand what is going on.
Here's another example.
Think not that I am come to send peace on earth: I came not to send peace, but a sword.
- Matthew 10:34 (KJV)
Did Jesus carry a sword? No He didn't.
This verse explains how the "sword" divides people, e.g. one must first choose God, even if that means abandoning loved ones. It's a figure of speech.
Here are the verses right below it.
For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law. And a man's foes shall be they of his own household. He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me.
- Matthew 10:35-37 (KJV)
Other times people will just grab a really cruel verse (which I won't put here), and point out that the Bible is very cruel. But just because cruel things happened, doesn't mean God approved of them.
The Bible records both good and bad.
So yeah, be aware of the "out of context" people. There's plenty of them out there that will just repeat what they hear, without ever trying to understand what the Bible is actually saying.
The Word of God never fails. (It is our interpretation that is faulty)