The Bible reveals that there will be a flurry of angelic activity in the end times.
The Four Living Creatures before the throne of God are the ones who will execute the first series of judgments that will mark the beginning of the Tribulation. It is in response to their commands that the Four Horsemen go forth with the Seal Judgments that result in the death of one-fourth of humanity (Revelation 6:1-8). Simultaneously, it is angels who will seal 144,000 Jews so that they will be supernaturally protected from all the judgments (Revelation 7:2-3).
When the second series of judgments begin — the Trumpet Judgments — it will be angels once again who serve as the instruments of God's wrath, resulting in the deaths of one-third of those still left alive (Revelation 8 and 9).
In the middle of the Tribulation, Satan will try one last time to take the throne of God, resulting in a war in the heavens between Satan and his demonic angels and Michael and his holy angels. Satan will be defeated, and he and his angels will be cast down to earth. His access to Heaven will be cut off permanently (Revelation 12:7-12).
In the second half of the Tribulation we are told that God will give Mankind one last opportunity to repent before He pours out His final wrath. He does this in a most unusual way. He sends forth three angels with very specific tasks.
The first angel, the one I like to refer to as "the Gospel Angel," is given the responsibility to proclaim the "eternal gospel" to "every nation and tribe and tongue and people" (Revelation 14:6). This will be the only time in history that God has allowed an angel to preach the Gospel. It will constitute the fulfillment of a prophecy made by Jesus when He said: "This gospel of the kingdom shall be preached in the whole world for a witness to all the nations, and then the end shall come" (Matthew 24:14).
The second angel will follow the first as he circumnavigates the earth. His task will be to proclaim the impending destruction of the kingdom of the Antichrist (Revelation 14:8). The third angel will follow along behind the first two. His role will be to issue a warning that anyone who worships the Antichrist and receives his mark will suffer God's wrath and torment in Hell (Revelation 14:9-11).
These three proclamations will be followed by the final outpouring of God's wrath, called the Bowl Judgments (Revelation 16). Once again, seven angels will execute these judgments (Revelation 16:1). Angels are also the ones who will destroy the capital city of the Antichrist in one hour on one day (Revelation 18).
The destruction of the Antichrist and his kingdom will bring to a close the terrible period of the Tribulation and will result in all the heavenly host breaking forth in celebration shouting, "Hallelujah!" (Revelation 19:1-7). Shortly thereafter, this same host of angels will return to earth with Jesus at His Second Coming (Matthew 24:30-31). They will gather the elect (those saved during the Tribulation who are still alive) from the four corners of the earth (Matthew 24:31).
The only information we are given about angels in the Eternal State is that the fallen angels, together with Satan, will be tormented in Hell forever (Matthew 25:41 and Revelation 20:10). No information is supplied regarding the godly angels.
I would assume that the holy angels would continue to serve God eternally and that they would also continue to minister to the Redeemed. I yearn to hear their stories about their interventions in my life. I look forward to their fellowship, and most of all, I look forward to hearing them sing!