What does Ephesians chapter 6 verse 17 is all about?

Ephesians 6: 17 reads. "Also, accept the helmet of salvation, and the sWord of the spirit, that is, God's Word".

The helmet of salvation:

A Roman soldier's helmet protected his head, face, and neck. Paul uses the helmet to symbolize a Christian's hope for salvation by God ( read 1 Th 5: 8

As a helmit protects the head, so salvation protects his mind, his thinking faculties. Satan subtly promotes such poisonous influences as selfishness, hatred, and disloyalty.

By focusing on the Christian hope--figuratively wearing hope like a helmet--the Christian rejects any negative influence on his thinking. Read Mark 7: 20-22; 2 Corinthians 4: 4: Revelation 12: 9.

The sWord of the spirit:

The sWord, one of the most important weapons used by Roman soldiers, is the only offensive weapon mentioned in Paul's illustration. Read Ephesians 6: 14-17.

The Greek Word translate "sWord" in this verse could refer to a short weapon with at least one sharp edge.

Christians today make good use of " God's Word", their main weapon for waging spiritual warfare. Read 2 Timothy 2: 15.

Paul is not suggesting that Christians use God's Word to harm others. Rather they tactfully use Scriptural truths to expose false teachings that mislead people and enslave them spiritually. Read John 8: 32; 17: 17; 2 Corinthians 10: 4,5

Just as soldier uses his sWord defensively to parry, or block, an enemy's blows, so Christians use God's Word to protect their minds and hearts against the deceptions of false teachers and against temptations to do wrong. Read Matthew 4: 1-11; 2 Timothy 3: 16

Ephesians 6: 11 reads: " Put on the complete suit of armor from God so that you may be able to stand firm against the crafty acts of the Devil"

1 John 5: 19 tells us that the whole world is lying in the power of the wicked one. And Revelation 12: 9 shows that the wicked one is the original serpent the one called Devil and Satan, who is misleading the entire inhabited earth".

So to answer your question: The helmit of salvation is to protect our mind and thinking ability and the sWord is God's Word, that is there to help us to stand firm against any false teachings.