I do not believe it can be lost,for God gave it,and the gifts and calling of God are without repentance on His part.
But it can be forfeited by the person,which they do not have to deny God,and Jesus,in that sense of them as a being,but back away from the lifestyle they once embraced at the beginning.
Luk 9:61 And another also said, Lord, I will follow thee; but let me first go bid them farewell, which are at home at my house.
Luk 9:62 And Jesus said unto him, No man, having put his hand to the plough, and looking back, is fit for the kingdom of God.
No person when they make a start following Christ,and correctly knowing that they have to abstain from sin,goes back to sinning,and holding unto sin,is not fit for the kingdom of God.
There are many people that claim Christ,that did not truly repent,and never received the Spirit,which they have a form of godliness,but deny the power thereof,and ever learning and never able to come to the truth,which Jesus will say He never knew them.
And we hear of preachers who will hand out a pamphlet,and they say a short prayer,and the preacher says,you are saved,but then the person basically keeps on living the way they were,and think I am saved,for there was no explaining what repentance means,and to receive the Spirit to abstain from sin,but left them hanging regarding what actually saves them,unless they search it out by being interested in the Bible.
Rom 11:20 Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:
Rom 11:21 For if God spared not the natural branches, take heed lest he also spare not thee.
Rom 11:22 Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off.
Old Testament,New Testament,the same rules apply,you back away from the goodness of God,what He laid down of what you should abide by,and do not correct it,holding unto sin instead of the goodness of God,you will be cut off.
Heb 3:10 Wherefore I was grieved with that generation, and said, They do alway err in their heart; and they have not known my ways.
Heb 3:11 So I sware in my wrath, They shall not enter into my rest.)
Heb 3:12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.
Heb 3:13 But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.
Heb 3:14 For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end.
Old Testament,New Testament,the same rules apply,do not depart from the living God by the deceitfulness of sin,which a person does not have to deny God,and Jesus,as a being,but holding unto sin causes a person to depart from God until they correct it.
In the Bible a lot of times it is not saying that they gave up on God,and Christ,and did not acknowledge them,but they went back to the sinful ways,and that is how they got in to an unsaved position until they correct it.
But many did not even repent correctly to start,and did not begin in the goodness of God,for they repented of their sins from the past,but then went to doing the sins that they were doing currently,and might ask for forgiveness every time they did them,but did not turn from them,or did not ask for forgiveness at all,and thought they were covered by the blood.
2Pe 2:20 For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.
2Pe 2:21 For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them.
2Pe 2:22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.
Gal 4:9 But now, after that ye have known God, or rather are known of God, how turn ye again to the weak and beggarly elements, whereunto ye desire again to be in bondage?
Any person putting their hand to the plough looking back is not fit for the kingdom of God,which some do escape the pollutions of the world,and have the knowledge of Jesus Christ,but then go back to the beggarly elements of the world,and is like a pig that was clean going back to her wallowing in the mire.
Gal 6:3 For if a man think himself to be something, when he is nothing, he deceiveth himself.
Gal 6:4 But let every man prove his own work, and then shall he have rejoicing in himself alone, and not in another.
Gal 6:5 For every man shall bear his own burden.
Gal 6:6 Let him that is taught in the word communicate unto him that teacheth in all good things.
Gal 6:7 Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap.
Gal 6:8 For he that soweth to his flesh shall of the flesh reap corruption; but he that soweth to the Spirit shall of the Spirit reap life everlasting.
Gal 6:9 And let us not be weary in well doing: for in due season we shall reap, if we faint not.
Whatever a person sows that is what they shall reap,and sin affects our relationship with God whether we confess Christ,or not.
Old Testament,New Testament,the same rules apply,and if you do not follow trouble is a brewing.
1Sa 15:22 And Samuel said, Hath the LORD as great delight in burnt offerings and sacrifices, as in obeying the voice of the LORD? Behold, to obey is better than sacrifice, and to hearken than the fat of rams.
1Sa 15:23 For rebellion is as the sin of witchcraft, and stubbornness is as iniquity and idolatry. Because thou hast rejected the word of the LORD, he hath also rejected thee from being king.
Joh 14:21 He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father, and I will love him, and will manifest myself to him.
Mat 28:20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen.
2Co 10:5 Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;
2Co 10:6 And having in a readiness to revenge all disobedience, when your obedience is fulfilled.
2Ti 2:19 Nevertheless the foundation of God standeth sure, having this seal, The Lord knoweth them that are his. And, Let every one that nameth the name of Christ depart from iniquity.
1Co 15:33 Be not deceived: evil communications corrupt good manners.
1Co 15:34 Awake to righteousness, and sin not; for some have not the knowledge of God: I speak this to your shame.
1Jn 3:10 In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother.
1Co 13:13 And now abideth faith, hope, charity, these three; but the greatest of these is charity.
No charity,love in action,towards all people,no faith,no salvation.
1Co 13:2 And though I have the gift of prophecy, and understand all mysteries, and all knowledge; and though I have all faith, so that I could remove mountains, and have not charity, I am nothing.
1Co 13:4 Charity suffereth long, and is kind; charity envieth not; charity vaunteth not itself, is not puffed up,
1Co 13:5 Doth not behave itself unseemly, seeketh not her own, is not easily provoked, thinketh no evil;
1Co 13:6 Rejoiceth not in iniquity(does not sin), but rejoiceth in the truth.
Jas 2:14 What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him?
Jas 2:15 If a brother or sister be naked, and destitute of daily food,
Jas 2:16 And one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit?
Jas 2:17 Even so faith, if it hath not works, is dead, being alone.
1Jn 3:17 But whoso hath this world's good, and seeth his brother have need, and shutteth up his bowels of compassion from him, how dwelleth the love of God in him?
1Jn 3:18 My little children, let us not love in word, neither in tongue; but in deed and in truth.
1Jn 2:15 Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him.
1Jn 2:16 For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world.
1Jn 2:17 And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.
1Ti 6:5 Perverse disputings of men of corrupt minds, and destitute of the truth, supposing that gain is godliness: from such withdraw thyself.
1Ti 6:6 But godliness with contentment is great gain.
1Ti 6:7 For we brought nothing into this world, and it is certain we can carry nothing out.
1Ti 6:8 And having food and raiment let us be therewith content.
1Ti 6:9 But they that will be rich fall into temptation and a snare, and into many foolish and hurtful lusts, which drown men in destruction and perdition.
1Ti 6:10 For the love of money is the root of all evil: which while some coveted after, they have erred from the faith, and pierced themselves through with many sorrows.
Jas 2:21 Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?
Jas 2:22 Seest thou how faith wrought with his works, and by works was faith made perfect?
Jas 2:24 Ye see then how that by works a man is justified, and not by faith only.
Love God.
Jas 2:25 Likewise also was not Rahab the harlot justified by works, when she had received the messengers, and had sent them out another way?
Jas 2:26 For as the body without the spirit is dead, so faith without works is dead also.
Love people.
Millions of people that confess Christ do not measure up to love,and have worldliness about them.
We cannot lose salvation,for God is always offering it if He called you,but we can forfeit it by not acting like Christ by the Spirit,which there are warnings in the Bible concerning it,and there does not need to be warnings if it were nt possible.
Php 2:12 Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.
Gal 6:9 And let us not be weary in well doing: for in due season we shall reap, if we faint not.
Rom 11:22 if thou continue in his goodness: otherwise thou also shalt be cut off.
1Co 9:26 I therefore so run, not as uncertainly; so fight I, not as one that beateth the air:
1Co 9:27 But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway.