The Psalms are bristling with verses about how God will destroy the wicked and give blessings on the righteous. I will be discussing the reasons for optimism given verses in the Psalms here and tie it up at the end.
Psalm 27:1, “The Lord is my light and my salvation; whom shall I fear? the Lord is the strength of my life; of whom shall I be afraid?” Here is one reason for optimism. David says that since the Lords is his light and salvation, he has nothing to be afraid of. He can trust that God will deliver him from opposition.
Psalm 23 is a great one I think: “1 The Lord is my shepherd; I shall not want. 2 He makes me lie down in green pastures: he leads me beside still waters. 3 He restores my soul: he leads me in the paths of righteousness for his name’s sake. 4 Yea, though I walk through the valley of the shadow of death, I will fear no evil: for thou art with me; thy rod and thy staff they comfort me. 5 Thou prepare a table before me in the presence of mine enemies: thou anoint my head with oil; my cup runs over. 6 Surely goodness and mercy shall follow me all the days of my life: and I will dwell in the house of the Lord for ever.” ‘…I shall not want…’ means that the Lord will provide all his needs. In verse 4, he is saying that even in the darkest of times, God is with him. Therefore he fears nothing, and God comforts him. ‘…my cup runs over.’ David says that God has granted him more than he needs. And verse 6 he is saying that all his life long, mercies and goodness will be granted him by God, and that he will go to heaven at the end of his days.
Psalm 46:1-3, “God is our refuge and our strength, a very present help in trouble. 2 Therefore will not we fear, though the earth be removed, and thought the mountains be carried into the midst of the sea; 3 Though the waters thereof roar and be troubled, though the mountains shake with the swelling thereof. Selah.” So the writer is saying that God is ‘a very present help’ in times of trouble. That God’s people will not fear though the earth itself seem to be breaking apart.
Psalm 91:3-6, “Surely he shall deliver thee from the snare of the fowler, and from the noisome pestilence. 4 He shall cover thee with his feathers, and under his wings shalt thou trust: his truth shall be thy shield and buckler. 5 Thou shalt not be afraid for the terror by night; nor for the arrow that flies by day; 6 Nor for the pestilence that walks in darkness; nor for the destruction that wastes at noonday.” So the writer claims that God will deliver his people from the snare and the pestilence. God will be a protection for them, and his truth will be their defense. He will shield his people from terrors and destruction at night and day.
So, all through the Psalms there is constant affirmation that God will protect His people from opposition and bless them with his mercies concerning all their needs.