This is a video of what I am assuming is an excerpt from a sermon by John Piper. In this excerpt Piper explains in very understandable language what is in many senses the essential difference between limited atonement (the Calvinistic view) and unlimited/universal atonement (the Arminian view)–two dominant views on the extent of the atonement. He clarifies what, in my opinion, are rather inappropriate terms (limited, unlimited, universal, etc.).
See also Shai Linne’s song “Limited Atonement,” which is featured at the beginning and end of this video clip.