A closing argument, summation, or summing up is the concluding statement of each party's counsel reiterating the important arguments for the trier of fact, often the jury, in a court case. A closing argument occurs after the presentation of evidence.
Jury instructions are given to the jury by the jury instructor, who usually reads them aloud to the jury. They are often the subject of discussion of the case, how they will decide who is guilty, and are given by the judge in order to make sure their interests are represented and nothing prejudicial is said.
The opening statement at the beginning of the trial is limited to outlining facts. This is each party's opportunity to set the basic scene for the jurors, introduce them to the core dispute(s) in the case, and provide a general road map of how the trial is expected to unfold.