@Berean if you are actually a strict adherer in the meaning of scripture, I'm surprised you don't view the context of what you pose in scripture.
Well to the next verse on your list…2 Corinthians 6:1
This verse pertains to spiritual immaturity and laziness of believers.
To remind many Corinthians that are saved to continue to work as servants of God and spread the gospel in the spirit of Christ. Many needed reminded that they were saved by the grace of God and not by themselves and just for their own benefit.
(2Co 6:1) And working together with him we entreat you not to receive the grace of God in vain.
Now this verse is the continuation of thought and context of the entire previous Chapter 5, at least. One must read it all before understanding and reading 2 Corinth 6:1.
This verse has nothing to do with losing salvation. It is all about being saved by the grace of God and then misusing or not growing in the spirit because of the things said in Chapter 5 at least. This is what is meant by receiving the grace of God in vain – for the wrong reason(s). This grace saved us but we can abuse this new life by not extending it to others because we are not working in spirit with Christ, in cooperation, in sanctification and personal spiritual growth. This is the point! We must speak of the gospel in the spirit of Christ, as to be blameless as we endure under hardships – read verse 2 and on…
(2Co 6:2) For He said: In a time of acceptance I hearkened to you, and in a day of salvation did I succour you. Behold, now is the time of acceptance; behold, now is the day of salvation.
(2Co 6:3) We aim to give no reason for stumbling in anything, that our ministry is not blamed.
(2Co 6:4) But in everything, commending ourselves as servants of God, in much patience, in afflictions, in necessities, in distresses,
(2Co 6:5) in stripes, in imprisonments, in tumults, in labours, in watchings, in fastings.
(2Co 6:6) In pureness, in knowledge, in patience, in kindness, in the Holy Spirit, in sincere love,
(2Co 6:7) in the word of truth, in the power of God; by the armour of righteousness on the right hand and on the left,
………………..etc
Paul is again echoing his determination of a reward and prize to win as a race at the judgement seat of Christ in the future. He wants the Corinthians to become as he, in heart and mind...not to have received God's grace for salvation for the wrong reasons. Paul wanted them to rediscover why God gave this grace to mankind for salvation in the first place.
Bless you,
APAK