God inspired Paul to an interesting arrangement of words here in 2 Corinthians 6.
Much like the figure of speech “Polysyndeton”, or many conjunctions, the preposition “in” is used repeatedly to emphasize each individual item.
2Co 6:3 KJV – Giving no offence in any thing, that the ministry be not blamed:
v4 – But in all things approving ourselves as the ministers of God, in much patience, in afflictions, in necessities, in distresses,
v5 – In stripes, in imprisonments, in tumults, in labours, in watchings, in fastings;
v6 – By pureness, by knowledge, by longsuffering, by kindness, by the Holy Ghost, by love unfeigned,
v7 – By the word of truth, by the power of God, <-en/dia-> by the armour of righteousness on the right hand and on the left,
In verses 3, 4, and 5 the English word “in” is the Greek word “en”.
[G1722] http://www.blbclassic.org/lang/lexicon/lexicon.cfm?Strongs=G1722&t=KJV
Then, in verse 6, the same Greek word changes to the English word “by” and includes the first two uses of “by” in verse 7. Then, in verse 7, the third usage of “by” is the Greek word “dia” which then continues.
[G1223] http://www.blbclassic.org/lang/lexicon/lexicon.cfm?Strongs=G1223&t=KJV