Every commandment God gives us to perform is a work. To believe is a work:

1 John 3:23  And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment.

The reason a baby cannot believe is because it is a work.
Babies are saved because God changes their heart.
The reason those who have never heard of Christ cannot believe is because it is a work.

Romans 10:14  How then shall they call on him in whom they have not believed? and how shall they believe in him of whom they have not heard? and how shall they hear without a preacher?

All sorts of people who have lived on this earth have never heard of Christ. If salvation is based on our believing then they have a legitimate claim that sending them to Hell would be unfair.
Even the devils believe:

James 2:19  Thou believest that there is one God; thou doest well: the devils also believe, and tremble.

Believing is often confused with having an intellectual understanding as to who Jesus is. People think their salvation is based on believing intellectually who Jesus is and so they rest on their work. We are only truly saved when we are “born again”. That is something we cannot do. Just as we contributed nothing to our first birth we can contribute nothing to our second birth.

John 3:3  Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.

How can a baby believe?
Alzheimer’s or an accident can render an extremely intelligent and competent person into a helpless human unable to make any kind of decision at all. They would be living and condemned to hell unless they made their freewill decision before their illness. What an awful state to be in!
The mentally retarded sin just like the rest of us, how would a severely retarded individual make this decision?

Luke 24:45  Then opened he their understanding, that they might understand the scriptures,

God has to open our understanding.
I’m going to repeat this question:
How can a baby believe?

I agree once saved, saved forever.
Did you know that John Wesley wrote a paper in support of Arminianism (salvation by freewill choice) in opposition to Calvinism (salvation by Gods choice)  where he claimed just the opposite. He claimed losing your salvation was essential to the freewill belief:
The Question, "What Is an Arminian?" Answered by a Lover of Free Grace
by John Wesley

*The Calvinists hold, Thirdly, that a true believer in Christ cannot possibly fall from grace. The Arminians hold, that a true believer may "make shipwreck of faith and a good conscience;" that he may fall, not only foully, but finally, so as to perish for ever.

* Indeed, the two latter points, irresistible grace and infallible perseverance, are the natural consequence of the former, of the unconditional decree. For if God has eternally and absolutely decreed to save such and such persons, it follows, both that they cannot resist his saving grace, (else they might miss of salvation,) and that they cannot finally fall from that grace which they cannot resist. So that, in effect, the three questions come into one, "Is predestination absolute or conditional?" The Arminians believe, it is conditional; the Calvinists, that it is absolute.

If God desired all to be saved He could do that, He is all powerful. The "all" talked about is ALL the elect. From ALL races and ALL nations, ALL sorts of different kinds of people.
He did not desire that any should go to hell, but every one would unless He saves (rescues) them.
Did "all the land of Judaea" become baptized by John the Baptist?
Or only certain people?

This goes to the word “all”. I’m going to copy and paste something I wrote elsewhere:
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One reason why so many misunderstand these verses is because of the word “all” that is used.
In the bible the word “all” can refer to all people or it can refer to all of a certain group of people.
For instance, to every one:

Romans 3:23  For all have sinned, and come short of the glory of God;

And references to a limited group of people:

Mark 1:5  And there went out unto him all the land of Judaea, and they of Jerusalem, and were all baptized of him in the river of Jordan, confessing their sins.

This cannot be ALL of the people of Judaea, there would have been close to two million people there at that time.  Certainly not all of the Pharisees and Sadducees would have been there.
Charles Spurgeon preached a sermon on this:

..." the whole world has gone after him" Did all the world go after Christ?  "then went all Judea, and were baptized of him in Jordan." Was all Judea, or all Jerusalem, baptized in Jordan? "Ye are of God, little children", and the whole world lieth in the wicked one". Does the whole world there mean everybody? The words "world" and "all" are used in some seven or eight senses in Scripture, and it is very rarely the "all" means all persons, taken individually. The words are generally used to signify that Christ has redeemed some of all sorts —some Jews, some Gentiles, some rich, some poor, and has not restricted His redemption to either Jew or Gentile ... (C.H. Spurgeon from a sermon on Particular Redemption)
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Jesus could have spoken openly to the people but He chose to speak in parables:

Mark 4:11  And he said unto them, Unto you it is given to know the mystery of the kingdom of God: but unto them that are without, all these things are done in parables:
Mark 4:12  That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them.

Does this sound like He wants all to be saved?

2 Thessalonians 2:11  And for this cause God shall send them strong delusion, that they should believe a lie:

Why would God send strong delusion if He wanted all to be saved.
Remember in the book of Mark the paralytic man. His friends lowered him down from the roof so Jesus could heal him of his illness. But what did The Lord do, He forgave him of his sins! He never asked for that.

Mark 2:5  When Jesus saw their faith, he said unto the sick of the palsy, Son, thy sins be forgiven thee.
 
True God never wanted anyone to go to hell but that is where everyone would go. We are so totally lost we can not do anything to save ourselves. Gods salvation is a rescue.
How would a baby believe?

I’ve skimmed through this thread and I’ve viewed many of the posts. I might have missed a person or two but so far all I’ve heard is works gospels.
The closest one not having a works gospel is lizmom. She recognized that it is a work to believe on Jesus Christ.
Her Quote:
Praise God for saving us. We are not all learned scholars. The work that we are to do is to believe in Jesus Christ.
She is right God saves us. We have nothing to do with it. Are we saved by keeping Gods commandments? We are commanded to believe.

1 John 3:23  And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment.

Why is it that not every one becomes saved. What separates us. Two brothers raised in the same home one becomes saved the other does not. Why, is one smarter, wiser, or more humble? Why does one come to salvation and the other does not?
The answer is the heart. Mans heart is totally corrupt. Absolutely no one has a heart that is able to truly believe.

Genesis 8:21  And the LORD smelled a sweet savour; and the LORD said in his heart, I will not again curse the ground any more for man’s sake; for the imagination of man’s heart is evil from his youth; neither will I again smite any more every thing living, as I have done.
 
Jeremiah 17:9  The heart is deceitful above all things, and desperately wicked: who can know it?

But God in His mercy has chosen to save some people. So He gives us a heart that will believe on Jesus. We become saved when God gives us a new heart.


Ezekiel 11:19  And I will give them one heart, and I will put a new spirit within you; and I will take the stony heart out of their flesh, and will give them an heart of flesh:
Ezekiel 11:20  That they may walk in my statutes, and keep mine ordinances, and do them: and they shall be my people, and I will be their God.


Hebrews 10:16  This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them;
Hebrews 10:17  And their sins and iniquities will I remember no more.

To believe is a work. Faith is a work.

1 Thessalonians 1:3  Remembering without ceasing your work of faith, and labour of love, and patience of hope in our Lord Jesus Christ, in the sight of God and our Father;

Believing and faith are results of salvation