One Minute They Believed & The Next They Were Throwing Stones at Christ

These people believed:

John 8:30 As he spake these words, many believed on him.

31 Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;

According to the free will gospel this means they became saved.

And yet, if we read on:

John 8:58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.

59 Then took they up stones to cast at him: but Jesus hid himself, and went out of the temple, going through the midst of them, and so passed by.

According to the context the very same people who "believed" are filling their hands with stones to cast at Christ.

Obviously, if they were stoning Christ, that's a strong indication they were not saved. But why? What happened to their salvation they obtained by their belief?

The answer is they might have given temporary intellectual assent and verbal confession – but that never changed their stony hearts. And a stony heart led them to cast stones at God in the flesh. Man's belief, insofar as true salvation is concerned, is worthless.