Have you ever heard someone say that there are "hundreds of contradictions in the Bible"? Well guess what. They're right.
GASP Whaaat? How can this be! I can't trust the Bible??
My faith is in vain!? Christianity is a lie?!?!

Whoa, whoa, not so fast!
Calm down.
You can trust the Bible, Christianity is still true.

"But...what about all those contradictions?"

Well, consider this:

Leviticus 5:9-10
"And he shall sprinkle of the blood of the [animal] sin offering upon the side of the altar; and the rest of the blood shall be wrung out at the bottom of the altar: it is a sin offering. And he shall offer the second for a burnt offering, according to the manner: and the priest shall make an atonement for him for his sin which he hath sinned, and it shall be forgiven him."

What is that verse teaching?
Answer: that in order for your sins to be forgiven, you need to offer an animal sacrifice to God.

Do Christians follow that today?
No!
Why in the world not?

Because:
1) We're not Israel
2) Jesus died on the cross as the final sacrifice for sin (Heb 10:12-14)
3) We don't live under the law, we live under grace (Rom 6:14)

So basically, when we read Leviticus (where it talks about having to sacrifice animals and follow the law in order to stay saved), we recognize that God was speaking to a different group of people (Hebrews) in a different time period (Old Testament) under different circumstances (the Law).

So when we come to other supposed "contradictions" in the Bible, we should always ask the following questions:
1) Who is speaking?
2) Who are they speaking to?
3) What are they speaking about?

When we answer those questions, we'll be able to see if a certain verse applies doctrinally to us, or if it was intended for someone else in a different time period.

But you say, "I still don't think there are any real contradictions in the New Testament. I mean, that's all for us, right? Matthew through Revelation, that's aaaall for us!" (btw we're not actually part of the New Testament)

Not so fast.
Are these verses for you?

Mark 16:16

"He that believeth and is baptized shall be saved; but he that believeth not shall be damned."

Luke 18:18,-20
"And a certain ruler asked him, saying, Good Master, what shall I do to inherit eternal life? And Jesus said unto him, Why callest thou me good? none is good, save one, that is, God. Thou knowest the commandments, Do not commit adultery, Do not kill, Do not steal, Do not bear false witness, Honour thy father and thy mother."

Hebrews 6:4-6
"For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, And have tasted the good word of God, and the powers of the world to come, If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame."

James 2:24

"Ye see then how that by works a man is justified, and not by faith only."

(compare those verses to 1 Cor 1:17, Rom 3:28, Eph 4:30, Gal 2:16)

"You mean the New Testament isn't all for us today??"
(By this I mean, not all the books (Matthew-Revelation) of the so-called "New Testament" are for us today. We're not doctrinally in the New Testament right now)

Yup!

"What is this madness?"

It's called "right division", and it's commanded in 2 Timothy 2:15.

2 Timothy 2:15
"Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth."

See, right there in that verse we're commanded to divide God's word (the Bible) based on the differences. We're supposed to recognize which books are written specifically to us (church age Christians), and which books are written to other people (such as Jews during the great tribulation).

When we recognize which parts are for us, and which parts are for others, all the "contradictions" suddenly disappear!

"So...which parts are for us today?"

Simple, the books written by the Apostle Paul.

"How do you know those are for us?"

Romans 11:13

"For I speak to you Gentiles, inasmuch as I am the apostle of the Gentiles, I magnify mine office:"

Ephesians 3:1-2
"For this cause I Paul, the prisoner of Jesus Christ for you Gentiles,
If ye have heard of the dispensation of the grace of God which is given me to you-ward:"

1 Corinthians 15:1-4
"Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures:"

Ephesians 2:8-9
"For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast."

That right there is the gospel of the dispensation of the grace of God.
The gospel that is applicable today.
The gospel of grace that we are saved by.
The gospel of faith, not of works.
Paul's gospel.

Read this article for more info on why we know Paul is speaking to us today: http://graceambassadors.com/midacts/choosing-your-part-of-the-bible

"Does this mean we should ignore any book not written by Paul?"

God forbid! Do you ignore the book of Genesis, just because it was written to a different dispensation?
Of course not!
Do we ignore the book of Leviticus, even though it was written under the law of Moses?
Never!

...but do we apply the doctrinal teachings found in those books to our salvation?
NO.

We do not go to Leviticus to learn how to be saved today, in the dispensation of the grace of God.
Rather, we instinctively know to go to Paul's books, particularly Romans, to learn how to be saved by grace through faith.

All scripture is profitable (2 Tim 3:16), but not all scripture is written specifically to you.

Still not convinced?
Okay.
Here's a list of legitimate, real contradictions found in the books of the New Testament.
Without rightly dividing the word of God, there's absolutely no way we can explain these contradictions.

In conclusion:

Not all scripture is written to you. Accept it.
All scripture is profitable, but in different ways.
The scripture written specifically to us in the dispensation of the grace of God is the books written by Paul (Romans through Philemon).
Other books, such as James, Hebrews, Matthew, Revelation, etc, are not written specifically to us.
To pull doctrinal teachings out of scripture not written to us would be a serious error indeed.
Instead, we need to first establish ourselves in the grace doctrine found in Paul's epistles.
Then, once we've got that understood, we can branch out into studying other books of the Bible, all the while remembering who they're written to, and at what time.

2 Timothy 2:15

"Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth."