Psalm 79 was written in the darkest moment of the history of Israel in the Old Testament. In 586BC the nation was decimated by the powerful Babylonian army. Jerusalem had been razed to the ground and the great and holy temple of Solomon with it. In addition to this many of the people had been slaughtered and the remainder were lead off into captivity in the region of Babylon. The Jews were reeling from this disaster for decades into their captivity and this psalm was written as a response to the event and an expression of the pain, anguish and anger that they felt from what they had suffered at the hands of the Babylonians.
One of the things that the people came to realise when they went into captivity in Babylon was that were suffering the very things that Moses spoke about in Deuteronomy 28:15ff. They had strayed far from God and were paying the price for it. Not the full price however. That would be paid for in Christ and so God was willing to forgive his people if they turned from him and was willing to answer their prayers if they called out to him. This is what they are doing in this psalm.
Psalm 79 expresses the grief and horror of what that nation had suffered. Though they had forfeited their divine protection by rebelling against God; though they had, in this sense, brought this upon themselves, it did not excuse the evils that were done to them by the Babylonians. So a key note of this psalm is a prayer for justice. Their enemies had gloated over them claiming that the gods of Babylon had defeated the God of Israel. They had mocked Israel saying “where is their God?” So the psalmist, believing that God always vindicates his own name, cries out for God to show that he is God. How long will God allow such injustice, boasting and mockery to continue? This is the tension of this psalm. The prayer is based firmly in the belief that God is just, that God will vindicate the glory of his name and that God will always forgive and raise his people up over their enemies if they turn back to him. For us today this psalm laments all that is broken in God’s world and raises a cry against the one who plunder God’s possession. It is a cry for justice over a world filled with evil. So long as our world is filled with such evil expressions like this will always be relevant and poignant.