When Moses calls Israel “a stiff-necked people” (Ex. 32:9), it is actually a form of praise, in a way.
He takes pride in this attribute: We cannot be so easily moved, like those for whom hearing one sermon by a Christian preacher leads them to proclaim, “I am born again!”
When attempting to move a Jew, every inch is an exhausting process.
Man’s glory is his free will, for his ability to decide is a kind of act of God.
Man can use his free will to his own detriment, or as an expression of glory and dignity.
The conclusion to be drawn is that man cannot be induced by external means to make a change in his essential nature.
Neither miracles nor bread from heaven can, in and of themselves, change human nature.
Human nature can change, but we must make these changes from within.
Rabbi Adin Steinsaltz