Like the other weapons “the helmet of salvation…” Ephesians 6:17 is both something we receive and something we apply.
A helmet is what is needed to protect our heads and therefore our minds.
Salvation is the free gift we receive when we believe in Jesus and accept His forgiveness for our sins:
"For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. For God did not send his Son into the world to condemn the world, but to save the world through him. Whoever believes in him is not condemned, but does not believe stands condemned already because he has not believed in the name of God’s one and only Son.” John 3:16-18
When we receive salvation we receive “the mind of Christ”:
“…we have the mind of Christ.” 1 Corinthians 2:16
While He was on earth Jesus Christ depended completely on His Father:
“…"I tell you the truth, the Son can do nothing by himself; he can do only what he sees his Father doing, because whatever the Father does the Son also does.” John 5:19 We can depend completely on the Father, also, and therefore have “the mind of Christ”.
God is the source of all wisdom:
“For the Lord gives wisdom, and from his mouth come knowledge and understanding.” Proverbs 2:6 That is why when we receive "the mind of Christ” we receive the means to all wisdom.
That means we can ask for God’s wisdom:
“If any of you lacks wisdom, he should ask God, who gives generously to all without finding fault, and it will be given to him.” James 1:5 We can know we receive wisdom no matter how we have fallen short of God’s plan for our lives.
King Solomon asked God for wisdom and:
“God gave Solomon wisdom and very great insight, and a breadth of understanding as measureless as the sand on the seashore.” 1 Kings 4:29 He was the wisest man who ever lived except for Jesus:
“…one greater than Salomon is here.” Matthew 12:42 Luke 11:31
We must apply “the helmet of salvation” by searching for and accepting the wisdom He gives:
“My son, if you accept my words and store up my commands within you, turning your ear to wisdom and applying your heart to understanding, and if you call out for insight and cry aloud for understanding, and if you look for it as for silver and search for it as for hidden treasure, then you will understand the fear of the Lord and find the knowledge of God. For the Lord gives wisdom, and from his mouth come knowledge and understanding.” Proverbs 2:1-6
Several passages show us that God desires to gives us wisdom:
“Surely you desire truth in the inner parts; you teach me wisdom in the inmost place.” Psalm 51:6
“Wisdom is supreme; therefore get wisdom. Though it cost all you have, get understanding.” Proverbs 4:7 Wisdom is worth sacrificing everything for; if we have God’s wisdom, we have everything.
He will teach us to make wise use of our time so we will be wise:
“Teach us to number our days aright, that we may gain a heart of wisdom.” Psalm 90:12
We must also apply “the helmet of salvation” by taking control of our mind to be obedient to Jesus. For instance, we must be careful about what we allow in our minds through T.V., music, books, magazines or a poor choice of friends:
“Above all else, guard your heart, for it is the wellspring of life.” Proverbs 4:23 We are not guilty for every thought the devil puts in our mind, but we are responsible what we allow to be put there or even pursue by letting ourselves be influenced by what we know is wrong.
Satan puts thoughts in our mind, but we are responsible for thoughts we let stay and dwell upon:
“When tempted, no one should say, "God is tempting me." For God cannot be tempted by evil, nor does he tempt anyone; but each one is tempted when, by his own evil desire, he is dragged away and enticed. Then, after desire has conceived, it gives birth to sin; and sin, when it is full-grown, gives birth to death.” James 1:13-15 We are guilty when we choose to sin and must face the consequences.
We are not guilty for every thought the devil puts in our minds. Even Jesus was tempted:
“Then Jesus was led by the Spirit into the desert to be tempted by the devil.” Matthew 4:1 (See Matthew 4:1-11, Mark 1:12-13, Luke 4:1-13)
Jesus, our high priest (authority, guide), understands when we are tempted because He came to earth as a man. He is completely man and completely God (“being in very nature God,” Philippians 2:6):
“For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are–yet was without sin. Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.” Hebrews 4:15-16 (See also Hebrews 2:18) We can “approach the throne of grace with confidence” because of God/Jesus who knows and controls everything loves us unconditionally.
Another remarkable promise—God will not give us more than we can bear:
“No temptation has seized you except what is common to man. And God is faithful; he will not let you be tempted beyond what you can bear. But when you are tempted, he will also provide a way out so that you can stand up under it.” 1 Corinthians 10:13 When you are tempted, do not think you have to give in but look for the “way out” which God has provided.
God will keep us in “perfect peace” if we will continually trust Him in all situations:
“You will keep in perfect peace him whose mind is steadfast, because he trusts in you.” Isaiah 26:3
The reason we have trials is so we will be “steadfast” or develop “perseverance”:
“Consider it pure joy, my brothers, whenever you face trials of many kinds, because you know that the testing of your faith develops perseverance. Perseverance must finish its work so that you may be mature and complete, not lacking anything.” James 1:2-4 Then we will be “mature and complete” and have “perfect peace”.
We can have a “continual feast”:
“All the days of the oppressed are wretched, but the cheerful heart has a continual feast.” Proverbs 15:15
We have the ability, because the Holy Spirit lives in us, to “…take captive every thought to make it obedient to Christ.” 2 Corinthians 10:5:
“The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds. We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ. And we will be ready to punish every act of disobedience, once your obedience is complete.” 2 Corinthians 10:4-6 Implied is that we can “demolish strongholds”, “arguments and every pretension that sets itself up against the knowledge of God” and “punish every act of disobedience” by taking “captive every thought to make it obedient to Christ”
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We can do this because we have the “helmet of salvation”, the weapon that is needed to protect our minds. We have access to God’s wisdom to do His will. God’s wisdom is a powerful weapon:
“A wise man has great power, and a man of knowledge increases strength…” Proverbs 24:5 Joseph rose from prison to palace in one day because of wisdom and governed Egypt with wisdom (Genesis 49). He listened well to God.