After these things the word of the Lord came to Abram in a vision: “Fear not, Abram, I am your shield. (Genesis 15:1 ESV)
Shield
While Captain America does occasionally throw his shield as a projectile weapon, shields are primarily defensive.
Shields stop harmful things from harming us. Shields keep us out of danger from dangerous things. Shields protect us when we need protection.
Because God loved Abram, He promised to be Abram’s shield.
Through all of Abram’s life, the Lord kept that promise, because God loved Abram. Abram was kept safe from Egyptians, from Canaanites, from Lot, from Sodom, from drought, from poverty, from Abram’s own fears, and even from the terrible effects of Abram’s sinfulness.
He shields us the same way, for the same reason. He loves us, so He protects us from sin. He loves us, so He protects us from His enemies, even when it is not obvious. He loves us, so He protects us from our own mistakes, bad decisions, and the results of our unrighteousness.
In fact, God’s love itself IS a shield. Because if He is for us (and is not that what love is?) who can be against us?