Free Will or Necessity?

Is the man Messiah Jesus free?  Does he experience perfect liberty in his choices or not?  And is he capable of doing something sinful?  Is it necessary that he always do what is good and right and true?

These questions (and their answers) have a bearing on the relation between free will and necessity in man.  If we are truly free, what necessarily follows?  Is perfect liberty inconsistent with the idea of things necessarily flowing from that liberty?

Jonathan Ewards writes this in miscellany 116a:

Although it be said that 'tis most absurd that there [should] be liberty and yet necessity, that these are most inconsistent; that is, that there should be liberty, when yet 'tis impossible in nature but that the things will be: yet 'tis not worth the while to dispute it, as if liberty and necessity were contraries, for they are not; and 'tis most certain, that that which in any proper sense is called liberty is certainly consistent with absolute necessity.  Thus the glorified [saints], or at least the glorified man Jesus, has as much liberty as any man; but yet 'tis absolutely impossible that he should sin.

Are you free?  That is to say, Are you unable to sin?