Good Friday is the English name for the day that commemorates the Roman Crucifixion of Jesus Christ. The word "good" uses its secondary meaning of "holy", not "desirable". In German, the name is "Karfreitag", meaning Mourning Friday. Finnish name "pitkäperjantai" and Swedish name "långfredag" mean Long Friday.
Until the 4th century AD, Jesus' death and resurrection were commemorated at the same time. Eventually, Good Friday was established to remember his death separately. Scripture specifies that Jesus was executed the day before a sabbath. With the weekly sabbath being Saturday, this would imply we died on Friday, which is why Friday was selected for the commemoration. This point is somewhat disputed, though. Scripture also says that Jesus was in the grave for three days and three nights, which means since he rose on Sunday, he must have died on Thursday. Since "sabbaths" can also refer to other holy days, a common theory is that Friday was Passover, thus that reference, and that he did indeed die on Thursday. Regardless, Friday is the day of commemoration.
Crucifixions were repeatedly used by the Romans, and Pontius Pilate was known (and later removed) for his particular brutality, even by Roman standards.
No one would voluntarily submit to such brutal treatment without the faith of life afterwards. All the Gospels describe Jesus as willingly accepting the Crucifixion, and Pilate even scourged (whipped) Jesus as a form of punishment less than death in the apparent hope that would satisfy the crowd. It did not.
Eyewitness John the Apostle described in Greek Jesus' final words and what happened next when He expired on the cross, at John 19:30. But how to translate those two brief, all-important sentences into English is not obvious. Here are some examples:
- When he had received the drink, Jesus said, "It is finished." With that, he bowed his head and gave up his spirit.
- When Jesus therefore had received the vinegar, he said, It is finished: and he bowed his head, and gave up the ghost.
- Jesus therefore, when he had taken the vinegar, said: It is consummated. And bowing his head, he gave up the ghost.
A modern discovery of the commercial use of the Greek term attributed to Jesus describe its meaning as "paid in full" (i.e., paying the debt incurred by sin in full) rather than "it is finished."
Good Friday is commemorated each year on the Friday of Holy Week, two days before Easter, which celebrates the resurrection of Jesus. It is not a national holiday in the United States, but is a holiday in some states, and many Christians (especially Catholics) use "personal leave time" to take the day off.
Jesus' death on the cross fulfills Old Testament Prophecy:
- Psalm 22:1, "My God, My God, why have You forsaken Me?..." 
- Isaiah 53:4-5, " 4 Surely he took up our infirmities and carried our sorrows, yet we considered him stricken by God, smitten by him, and afflicted. 5 But he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed."
- Wisdom 2:16-20, " 16 We are considered by him as something base, and he avoids our ways as unclean; he calls the last end of the righteous happy, and boasts that God is his father. 17 Let us see if his words are true, and let us test what will happen at the end of his life; 18 for if the righteous man is God's son, he will help him, and will deliver him from the hand of his adversaries. 19 Let us test him with insult and torture, that we may find out how gentle he is, and make trial of his forbearance. 20 Let us condemn him to a shameful death, for, according to what he says, he will be protected."
- For example, in Texas it is an "optional holiday" (one which an employee can use in lieu of another holiday).