The "Call" to ministry

We hear the phrase, "I was called into ministry", but what does it really mean?, and how do you know if you have really been "called"?
First of all the term, "Call" is pretty mysterious sounding. It is not something audible to the ear, but it is more audible to the heart. It's probably more of a "sense."
Basically what someone is saying when they use that phrase is that they believe that God has actually prepared them and set them apart for some ministry opportunity.
Here's where a lot of people get in trouble. They say, "God has called me to become a Pastor."
But in many cases it wasn't a call from God, it was a desire on their part that they confused for a call.
Here is a couple of scriptures to show a call versus a person's own desire.

Jer. 20:9 But if I say, "I will not mention Him or speak anymore in His name," His word is in my heart like a fire, a fire shut up in my bones. I am weary of holding it in, indeed, I cannot.

1 Cor 9:16 Yet when I preach the gospel, I cannot boast, for I am compelled to preach. Woe to me if I do not preach the gospel!

Here are 4 ways to know if you are being "Called":
1. You can't NOT do it. (see scriptures above)
2. You will make whatever sacrifice necessary to follow
3. You will have a passion to do whatever it is you're being called to do that will cause you to constantly think about it. You will wake up in the middle of the night thinking about it. You will wake up in the morning thinking about it. You will go to sleep thinking about it. You will dream about it.
4. The passion will only increase with time (If it fades out, it was probably just your desire, not a true calling)