Tsiyon Heights Messianic Radio

1 Amid this, I saw four angels standing over the four corners of the earth, holding the four winds of the earth, so that no wind would blow on the earth, or on the sea, or on any tree.
2 I saw another angel ascend from the sunrise, having the seal of the living God. He cried with a loud voice to the four angels to whom it was given to harm the earth and the sea,
3 saying, “Don’t harm the earth, neither the sea, nor the trees, until we have sealed the bondslaves of our God on their foreheads!”
4 I heard the number of those who were sealed, one hundred forty-four thousand, sealed out of every tribe of the sons of Israel.

Revelation 7:1-4

Four angels hold back the four winds of the Tribulation while the angel ascending from the sunrise, having the seal of the living God,
seals 144,000 bondslaves.

 "There will be signs in the sun, moon, and stars."  Luke 21:25

And when He had opened the sixth seal, I looked, and behold, there was a great earthquake. And the sun became black, like sackcloth of hair, and the whole moon became like blood. And the stars of heaven fell to the earth, even as a fig tree casts her untimely figs when she is shaken by a mighty wind. And the heaven departed like a scroll when it is rolled together. And every mountain and island were moved out of their places. Revelation 6:12-14

And the kings of the earth, and the great men, and the rich, and the chief captains, and the mighty men, and every bondman, and every freeman, hid themselves in the dens and in the rocks of the mountains. And they said to the mountains and rocks, Fall on us and hide us from the face of Him sitting on the throne, and from the wrath of the Lamb; for the great day of His wrath has come, and who will be able to stand? Revelation 6:15-17

What will happen?   ..When?   What do these signs mean?