The only thing that every man woman and child has is the ability to trust, believe, hence the true meaning of faith. But no one is able to keep it. Faith in the Biblical context is an action or to be more accurate the beginning of an action, with expectation of fulfillment. It is not an object as many religious like to keep it in the mind set of the believer. So as to give themselves the delusion of being in control of, and the definers of, faith. The definition of the Christian faith is not defined by so-called Christians:
Gal:2:16: Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.
Phil:3:9: And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith:
Note the phrase "faith of Christ". Hence we are not the source of the faith given in Christ. Paul plainly says in Galicians with the presumed understanding that if you are not justified, you have no salvation, because you can’t be in God’s Presence without justification. And even though he saying "we have believed", he acknowledges that it is still the Faith OF Christ that justifies. You must be justified to be in God’s Presence seen Righteous that is acknowledged by God as Righteousness. Not acknowledged by men, but acknowledged by God.
It’s a continuous path that only the Presence of God through His Word can keep you on. And if you are not on it, then you have not the Presence of God with you in the first place. God doesn’t fail, nor falter. Nor does the Faith that is of Christ.
If one understands just what the Lord God judges by, then one can understand if they are in His care or not. God will never turn the faithful away, because He is Faithful and what faithful is. Therefore if He gives His Word to somebody, He keeps it. The person He gives His Word to isn’t able to keep it. Just as anything else in creation can’t keep God’s Word. Nothing can fulfill God’s Word but God Himself. Either one submits to God’s fulfillment of His Word, which results in life and living. Or one seeks the fulfillment of what they see as good in their own judgement, which results in death.
So to say that God can’t keep you, is to not trust in the Faith that is of Christ that is seen by God as what is Righteousness. Therefore, one doesn’t have the faith, belief or trust in the first place, that is required to be in God’s Presence.
If you don't trust that He can keep you, then you are not kept.