"Even now," declares the LORD, "return to me with all your heart, with fasting and weeping and mourning."
Joel 2:12

"See, I will send you the prophet Elijah before that great and dreadful day of the LORD comes. He will turn the hearts of the fathers to their children, and the hearts of the children to their fathers; or else I will come and strike the land with a curse."
Malachi 4:5-6

In the last days, God says, I will pour out my Spirit on all people. Your sons and daughters will prophesy, your young men will see visions, your old men will dream dreams.
Acts 2:17

And when he had taken it, the four living creatures and the twenty-four elders fell down before the Lamb. Each one had a harp and they were holding golden bowls full of incense, which are the prayers of the saints.
Revelation 5:8

Another angel, who had a golden censer, came and stood at the altar. He was given much incense to offer, with the prayers of all the saints, on the golden altar before the throne. The smoke of the incense, together with the prayers of the saints, went up before God from the angel's hand. Then the angel took the censer, filled it with fire from the altar, and hurled it on the earth; and there came peals of thunder, rumblings, flashes of lightning and an earthquake.
Revelation 8:3-5

I have posted watchmen on your walls, O Jerusalem; they will never be silent day or night. You who call on the LORD, give yourselves no rest, and give him no rest till he establishes Jerusalem and makes her the praise of the earth.
Isaiah 62:6-7