Heb 1:14, Acts 12:5-11, Acts 27:23-24
In the Old Testament, God sent an angel to protect Daniel, who was thrown into the lions' den. (Da 6:19-22)
Da 6:19 Then the king arose very early in the morning, and went in haste unto the den of lions. 20 And when he came to the den, he cried with a lamentable voice unto Daniel: and the king spake and said to Daniel, O Daniel, servant of the living God, is thy God, whom thou servest continually, able to deliver thee from the lions? 21 Then said Daniel unto the king, O king, live for ever. 22 My God hath sent his angel, and hath shut the lions' mouths, that they have not hurt me: forasmuch as before him innocency was found in me; and also before thee, O king, have I done no hurt.
God sends angels to protect and guide us who have been saved. (Heb 1:14, Acts 12:5-11, Acts 27:23-24)
Heb 1:14 Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?
Acts 12:5 Peter therefore was kept in prison: but prayer was made without ceasing of the church unto God for him. 6 And when Herod would have brought him forth, the same night Peter was sleeping between two soldiers, bound with two chains: and the keepers before the door kept the prison. 7 And, behold, the angel of the Lord came upon him, and a light shined in the prison: and he smote Peter on the side, and raised him up, saying, Arise up quickly. And his chains fell off from his hands. 8 And the angel said unto him, Gird thyself, and bind on thy sandals. And so he did. And he saith unto him, Cast thy garment about thee, and follow me. 9 And he went out, and followed him; and wist not that it was true which was done by the angel; but thought he saw a vision. 10 When they were past the first and the second ward, they came unto the iron gate that leadeth unto the city; which opened to them of his own accord: and they went out, and passed on through one street; and forthwith the angel departed from him. 11 And when Peter was come to himself, he said, Now I know of a surety, that the Lord hath sent his angel, and hath delivered me out of the hand of Herod, and from all the expectation of the people of the Jews.
Acts 27:23 For there stood by me this night the angel of God, whose I am, and whom I serve, 24 Saying, Fear not, Paul; thou must be brought before Caesar: and, lo, God hath given thee all them that sail with thee.