That's just it they don't warn of loosing salvation … they can't when these two verses below must fit into this discussion
verse 1- 1 John 2:19
19 They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
This verse, above, states if you are in Christ 'of us' then you will remain with us... or else you were never of us
verse 2- Titus 3:5-7
5 Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost;
6 Which he shed on us abundantly through Jesus Christ our Saviour;
7 That being justified by his grace, we should be made heirs according to the hope of eternal life.
Now these verses you have listed as loss of salvation- are all taken out of Biblical follow through, as ignoring the two verses above I might add- [incorporate these two clear and distinct teachings of God's Word above]…
so when you bring them into realm of what is said above- we find it is Scripture placing the light upon those who come to what they think is salvation but is not; and there will be many I might add
10 Verily, verily, I say unto you, He that entereth not by the door into the sheepfold, but climbeth up some other way, the same is a thief and a robber.
21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
22 Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?
when all the verses of the Bible are brought to bear upon salvation this is the way it is:
When one comes to Jesus with nothing to barter with but looks to Him alone to save... they will repent of all that they are and cry out to Jesus to save them! Their heart door opens to Jesus and He enters into them by The Person of The Holy Spirit and they are regenerated into a new being ('ye must be born again')… God seals the deal with this promise
28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.
29 My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand.
30 I and my Father are one.