"a people helped by the L-rd": a people whose help is only in the Shechinah.
"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."
"and the sword of your pride": The Holy One Blessed be He said to Moses: "I am destined to restore to Israel the adornment that He took from them at Chorev, as it is written (Shemoth 33:6) "And the children of Israel divested themselves of their adornment (which had been bequeathed them) at Mount Chorev." I have taken an oath that I will restore it to you, viz. (Isaiah 49:18) "I swear, says the L-rd, that you will clothe yourselves with all of them like adornments, and you will tie them to you like a bride."