In Scripture, then, we uniformly read that angels are heavenly spirits, whose obedience and ministry God employs to execute all the purposes which he has decreed, and hence their name as being a kind of intermediate messengers to manifest his will to men. The names by which several of them are distinguished have reference to the same office. They are called hosts, because they surround their Prince as his court,—adorn and display his majesty,—like soldiers, have their eyes always turned to their leader’s standard, and are so ready and prompt to execute his orders, that the moment he gives the nod, they prepare for, or rather are actually at work. In declaring the magnificence of the divine throne, similar representations are given by the prophets, and especially by Daniel, when he says, that when God stood up to Judgment, “thousand thousands ministered unto him, and ten thousand times ten thousand stood before him,” (Dan. 7:10). As by these means the Lord wonderfully exerts and declares the power and might of his hand, they are called virtues. Again, as his government of the world is exercised and administered by them, they are called at one time Principalities, at another Powers, at another Dominions (Col. 1:16; Eph. 1:21).2Calvin, from there, proceeded to treat the subject with the utmost care, bringing the reader to the place of understanding the prominent role that Angels play in the life of believers. For instance, in 1.14.5, he explained:
The point on which the Scriptures specially insist is that which tends most to our comfort, and to the confirmation of our faith, namely, that angels are the ministers and dispensers of the divine bounty towards us. Accordingly, we are told how they watch for our safety, how they undertake our defense, direct our path, and take heed that no evil befall us. There are whole passages which relate, in the first instance, to Christ, the Head of the Church, and after him to all believers. “He shall give his angels charge over thee, to keep thee in all thy ways. They shall bear thee up in their hands, lest thou dash thy foot against a stone.” Again, “The angel of the Lord encamps around them that fear him, and delivers them.” By these passages the Lord shows that the protection of those whom he has undertaken to defend he has delegated to his angels.3This brings us back again to the question of whether or not each believer has one, single guardian angel entrusted to watch over him or her. Many have suggested so based on an appeal to Jesus' teaching in Matthew 18:10 and to a passing reference to Peter's "Angel" in Acts 12:15. In the passage in Matthew 10, our Lord says, "Take heed that you do not despise one of these little ones, for I say to you that in heaven their angels always see the face of My Father who is in heaven." A cursory reading--taken together with the Acts 12 passage--makes such an interpretation seemingly viable. At first glance, it appears that our Lord Jesus is teaching that each of His "little ones" (i.e. believers) are watched over by an Angel. However, as B.B. Warfield, has helpfully noted in his article "The Angels of Christ's Little Ones:"
While many other objections may be raised about any sort of biblical teaching regarding individual "guardian angels" entrusted by God to watch over individual believers, of this much we can be sure--God will not spare to send the entire host of heaven to the aid of His people if He so chooses. They are, after all, called "ministering spirits" in the book of Hebrews, where we learn that they are "sent forth to minister to those who will inherit eternal life." We may not be sure as to whether or not one specific angel is appointed to a specific believer, but our faith is stirred as we step back and have our eyes opened to see "the mountain full of horses and chariots of fire all around Elisha" and his servant as they were being pursued by the King of Syria (2 Kings 17). We are built up in faith as we hear our Lord Jesus tell the eleven disciples, "do you think that I cannot now pray to My Father, and He will provide Me with more than twelve legions of angels?"--an entire legion of Angels for each of them (Matt. 26:53). What comfort is derived from the thought that "if God did not spare His own Son, but gave Him up for us all" how will He not employ the service of the army of heaven to bring His children to glory. 1. John Calvin Institutes of the Christian Religion 1.14.3 2. Ibid. 3. Ibid., 1.14.6 4. B.B. Warfield, "The Angels of Christ's Little Ones" in The Bible Student (Columbia, S.C.: The R.L. Bryan Co., 1902) p. 241
"The real difficulty of explaining these passages by the aid of the notion of "guardian angels" is that this notion does not in the least fit their requirements. Where should a "guardian angel" be, except with his ward? That is the essential idea of a "guardian angel;" he is supposed to be in unbroken attendance upon the saint committed to his charge. But neither in Mat. 18:10, nor in Acts 12:15 are the angels spoken of found with their wards; but distinctly elsewhere. Our Lord says that the angels of the little ones of which he speaks, are not on earth with their charges, but "in heaven, constantly beholding the face of my Father who is in heaven." It was because the Christians gathered in Mary's house could not believe it was the imprisoned Peter who was at the door, that they supposed it must be his angel. It is thus characteristic of these angels mentioned in the New Testament that they are not constantly with those whose angels they are. If "guardian angels" are intended, one wonders how it gives force to the warning that we would do well not to despise a single one of these "little ones," to be told that their "guardian angels" are not with them but are "always in heaven, beholding the face of my Father which is in heaven." And one wonders whether if Peter had a guardian angel at all, it would not be just the time when he would be supposed to be with him, when he lay languishing in prison, expectant of the worst on the morrow. One knows that God's angel—which seems something better than Peter's angel—was actually with Peter, ministering to his needs at this exact time."4