Please turn over to Hebrews 1, verse 13. The writer of the epistle to the Hebrews is contrasting Jesus Christ with the angels, and this is how he expresses it.
This means that since we are in God's church, God's angels serve us under Christ's leadership. And that is how this epistle describes an angel, as a ministering spirit sent forth to serve and to attend to us, the heirs of the world to come, the betrothed bride.
And since they are unseen and not visible, we might tend to neglect appreciating the ministry of the angels. We might not be as thankful for them as we should be. But whether we realize it or not, angels are watching over us under the Groom's direction. They are always with us, providing physical and spiritual protection and meeting other needs in our lives. Although we do not see them, that does not matter. We often overlook the most important things, and we only notice the temporary and visible ones in this life, for the most part.
Still, we are surrounded by angels, and they are assigned to watch over us and serve us. Christ's servants are our servants because He is the Bridegroom and we are His betrothed bride. They are working on our behalf in ways we do not understand. Since their creation they have served God and Christ, and because of our new relationship they are now our servants who serve us, not fully, but in a temporary sense until we are changed into spirit beings.
But it is essential to recognize that ministering spirits being surround us and nothing can harm us unless God allows it. So we should not fear. The angels are sent by Christ under His Father's authority to watch over us.