Midrasz do Samuela II 22:3

(Exodus 14:20) "And it (the cloud) came between the camp of Egypt and the camp of Israel, and it was cloud and darkness" — cloud for Israel and darkness for Egypt; Israel in the light, and Egypt in the dark, as in (Ibid. 10:23) "One man did not see another, and no man rose from his place for three days." And thus do you find in time to come, viz. (Isaiah 60:1) "Arise, shine, for your light has come, and the glory of the L rd has shone upon you." Why? (Ibid. 2) "For, behold, the darkness covers the earth, and thick clouds, the peoples, and upon you the L rd will shine, and His honor will be seen upon you." And, what is more, he who is enveloped in darkness will see him who is enveloped in light. For the Egyptians, steeped in darkness, saw Israel in the light, eating, drinking and rejoicing. And they shot arrows and projectiles upon them, and the cloud and the angel protected them. And it is written (II Samuel 22:3) "My Shield, the horn of my salvation, my fortress and my refuge, my savior — You will save me from violence." And it is written (Ibid. 31) "He is a Shield to all who take shelter in Him."

Another interpretation (of 22:11): BUT < THE ANGEL OF THE LORD > CALLED UNTO HIM. Abraham said to him: Who are you? He said to him: I am an angel. Abraham said to him: When the Holy One told me to sacrifice him, he told me so himself. So now I ask that he himself tell me < to stop >. Immediately the Holy One, having opened the firmament and the lower sky, said to him (in Gen. 22:16): I BY MYSELF HAVE SWORN. Abraham said to him: So now you have sworn! But I also have sworn that I am not coming down from this altar until I say everything that I must. He said to him: Say everything that you must. Abraham said to him: Did you not tell me that what you would raise up from me would completely fill up the world, as stated (in Gen. 15:5): AND COUNT THE STARS … SO SHALL YOUR SEED BE? The Holy One said to him: Yes. He said to him: From whom? He said to him: From Isaac. He said to him: And did you not tell me that you would multiply my children like the dust, as stated (in Gen. 28:14): AND YOUR SEED SHALL BE LIKE THE DUST OF THE EARTH? The Holy One said to him: Yes. He said to him: From whom? He said to him: From Isaac. He said to him: Just as I had the right to talk back to you and did not say anything to you, O Sovereign of the World—Yesterday you said (in Gen. 21:12): FOR IN ISAAC SHALL SEED BE SUMMONED FOR YOU; but now you are saying (in Gen. 22:2): AND OFFER HIM THERE AS A BURNT OFFERING. Yet I suppressed my urge and did not talk back to you. < Just as I have acted in this way >, you also, when Isaac's children sin against you and enter into sorrow, remember on their behalf the binding of their father Isaac. Forgive them, and redeem them from their sorrows. The Holy One said to them: You have had your say; I will also have mine. The Holy One said to him: Your children are going to be sinful in my presence, < and I am going > to judge them on New Year's day. However, if they ask me to forgive them and blow a shofar before me on that day—Abraham said to him: And what is a shofar? The Holy One said to him: Do you not know? He said to him: Turn around and look. Immediately (as we read in Gen. 22:13): THEN ABRAHAM LIFTED HIS EYES [TO LOOK AND THERE WAS A RAM BEHIND HIM CAUGHT IN A THICKET ON HIS HORNS]. It says here nothing but ON HIS HORNS. He said to him: They will blow on a horn before me, and I will forgive their sins. In that hour he gave praise and thanksgiving to the Holy One; and that is how David gave praise¹⁷⁷Gk.: kalos. (in II Sam. 22:3 // Ps. 18:3 [2]): < THE LORD … MY SHIELD > AND MY HORN OF SALVATION. And it says also (in Joel 2:15): BLOW A SHOFAR IN ZION. The beginning (of the verse) concerns New Year's day. Then afterwards (ibid., cont.): SANCTIFY A FAST. This refers to the Day of Atonement, < which comes > after ten days, on which the Holy One forgives their sins. Thus it is stated (in Lev. 16:30): FOR ON THIS DAY ATONEMENT SHALL BE MADE FOR YOU…. Blessed are you, O Israel! How the Holy One has loved you! < He has done for you > what he has not done for any people or tongue, as stated (in Ps. 111:6): HE HAS DECLARED THE POWER OF HIS WORKS TO HIS PEOPLE < IN GIVING THEM THE HERITAGE OF THE NATIONS >. It is also written (in Ps. 147:19): HE DECLARES HIS WORDS TO JACOB, HIS STATUTES AND HIS ORDINANCES TO ISRAEL. And it is written (in vs. 20): HE HAS NOT DONE SO FOR ANY NATION; AND, AS FOR HIS ORDINANCES, THEY HAVE NOT KNOWN THEM. HALLELUJAH.

"helped by the L-rd, the Shield of your salvation": as in (II Samuel 22:3) "G-d is my rock, in whom I take shelter, my Shield, and the horn of my salvation."