This study builds a little bit on another one I posted last month, Shadows And Wings. The idea of God being our shield (and buckler) certainly gives us the idea of protection. There are a range of shields that compass the believer in Scripture.
Though these first two passages don't mention God as a shield, His protection is certainly contrasted with that of man's weapons of war (see 2 Corinthians 10:3-5):
1 Samuel 17:45-47 Then said David to the Philistine, Thou comest to me with a sword, and with a spear, and with a shield: but I come to thee in the name of the LORD of hosts, the God of the armies of Israel, whom thou hast defied. This day will the LORD deliver thee into mine hand; and I will smite thee, and take thine head from thee; and I will give the carcases of the host of the Philistines this day unto the fowls of the air, and to the wild beasts of the earth; that all the earth may know that there is a God in Israel. And all this assembly shall know that the LORD saveth not with sword and spear: for the battle is the LORD'S, and he will give you into our hands.
2 Kings 19:32-34 Therefore thus saith the LORD concerning the king of Assyria, He shall not come into this city, nor shoot an arrow there, nor come before it with shield, nor cast a bank against it. By the way that he came, by the same shall he return, and shall not come into this city, saith the LORD. For I will defend this city, to save it, for mine own sake, and for my servant David's sake.
In most of the passages in this study, the word for shield or buckler means: "a shield (i.e. the small one or buckler); figuratively, a protector." I have noted the places where a different word is used.
The Lord is your shield:
2 Samuel 22:3 The God of my rock; in him will I trust: he is my shield, and the horn of my salvation, my high tower, and my refuge, my saviour; thou savest me from violence.
Psalms 3:3 But thou, O LORD, art a shield for me; my glory, and the lifter up of mine head.
Psalms 18:2 The LORD is my rock, and my fortress, and my deliverer; my God, my strength, in whom I will trust; my buckler, and the horn of my salvation, and my high tower.
Psalms 18:30 As for God, his way is perfect: the word of the LORD is tried: he is a buckler to all those that trust in him.
Psalms 28:7 The LORD is my strength and my shield; my heart trusted in him, and I am helped: therefore my heart greatly rejoiceth; and with my song will I praise him.
Psalms 59:11 Slay them not, lest my people forget: scatter them by thy power; and bring them down, O Lord our shield.
Psalms 84:9 Behold, O God our shield, and look upon the face of thine anointed.
Psalms 84:11 For the LORD God is a sun and shield: the LORD will give grace and glory: no good thing will he withhold from them that walk uprightly.
Psalms 119:114 Thou art my hiding place and my shield: I hope in thy word.
Psalms 144:2 My goodness, and my fortress; my high tower, and my deliverer; my shield, and he in whom I trust; who subdueth my people under me.
The Lord is the shield of your help:
Deuteronomy 33:29 Happy art thou, O Israel: who is like unto thee, O people saved by the LORD, the shield of thy help, and who is the sword of thy excellency! and thine enemies shall be found liars unto thee; and thou shalt tread upon their high places.
Psalms 33:20 Our soul waiteth for the LORD: he is our help and our shield.
Psalms 115:11 Ye that fear the LORD, trust in the LORD: he is their help and their shield. (See also verses 9-10)
His salvation is your shield:
Psalms 18:35 Thou hast also given me the shield of thy salvation: and thy right hand hath holden me up, and thy gentleness hath made me great.
The Lord will surround you with favour as a shield:
Psalms 5:12 For thou, LORD, wilt bless the righteous; with favour wilt thou compass him as with a shield.
The word for shield here is interesting. It means "a (large) shield (as if guarding by prickliness)." The favour God surrounds the righteous with is as a large prickly shield, warding off the attacks of our spiritual enemies. This same word for shield is also used in Psalm 91:4 (see next point).
His truth is your shield:
Psalms 91:4 He shall cover thee with his feathers, and under his wings shalt thou trust: his truth shall be thy shield and buckler.
In this verse, the word for buckler here means "something surrounding the person; ie. a shield." God's Word is a defense for us - a protection that surrounds us completely. When we walk according to God's Word, when we walk in truth, the Lord and His Word completely protect and surround us!
The Shield of Faith:
Genesis 15:1 (in a passage about faith) contains the first reference to a shield in the Bible, and this passage (on the armour of God) contains the last reference:
Ephesians 6:16 Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked.
The word for shield here means "a large shield (as door-shaped)." Certainly a shield this large (spiritually-speaking) can block any attack the devil throws at us! But notice, we are to take this shield up - that means we are responsible to get into the Word of God ourselves and to equip ourselves with its precepts, its principles, and its promises - and when the Devil comes to throw his fiery darts at us, our faith will protect us from his wiles and doubts.
Notice how many of these passages about the Lord God being the believer's shield hinge upon our trusting in Him and walking uprightly before Him. If we disregard His Word and live in rebellion, He is not our shield - but if we walk in faith, He surrounds us and protects us day by day - no matter what battles we may face!
Proverbs 2:7 He layeth up sound wisdom for the righteous: he is a buckler to them that walk uprightly.
Proverbs 30:5 Every word of God is pure: he is a shield unto them that put their trust in him.
If you are a believer in the Lord Jesus Christ, walking according to truth, God says to you:
For more studies based on Genesis 15:1:
Genesis 15 - Fear Not - Part One
Genesis 15 - Fear Not - Part Two
Genesis 15 - Fear Not - Part Three
Genesis 15 - Fear Not - Part Four
Genesis 15 - Thy Exceeding Great Reward
For more studies in Genesis (with Genesis as the springboard):