Mark 13:26-27 (ESV)
And then they will see the Son of Man coming in clouds with great power and glory.  And then he will send out the angels and gather his elect from the four winds, from the ends of the earth to the ends of heaven.
It is now, after the tribulation, when Jesus comes in glory, that the elect are gathered by the angels. The elect are not spared the tribulation. In fact quite the opposite, the tribulation is directed at them. This might cause many to fear. It shouldn’t. For Paul it was a source of joy that he should be chosen to suffer for Jesus, on account of Jesus. The epistles are full of encouragement to stand fast in the tribulation. The idea that we should be spared tribulation should be anathema to us. It is really a bizarre teaching, an anti Christian teaching that says we should be spared persecution, and that is what the tribulation is meant to be. Sure people who are not Christian experience tribulation, but they do so for naught, in a meaningless manner. But when Christian suffer in this world we suffer for Christ. Because it is aon account of him that we live in this world, no longer living for ourselves, but living for him who died on the cross for us. We are his servants now. The world knows this. They hate us for it. But we live every day to his glory serving him, by serving our neighbor in Christian love. So just as Christ was hated, spit upon reviled, well we should expect no less. And yet count every day we suffer in this world another day of grace in which God has allowed us to serve our neighbors in love, share the gospel with them, and do his will. Every day we suffer this insufferable world, is a day of grace for which we can be thankful, another day God has used us to do his will in this world. So fear not the tribulation, rejoice that you are counted worthy to suffer for Christ.