In act IV scene 1 what effects does the image of the "bloody child" have on this scene and the play in general?

In act 4 scene 1 the Second
Apparition that meets Macbeth is a bloody child. The
image relates to Macduff who was prematurely born and who was supposed to behead Macbeth
in the end. The apparition induces in Macbeth a false sense of
security:

Be
bloody, bold and resolute; laugh to scorn

The power of man,
for none of woman born

Shall harm
Macbeth.

Macbeth fails to
read the equivocation and regards himself as
unputdownable.

Later, when in act 5 scene 7 Macbeth
sarcastically tells Macduff that his effort to kill Macbeth would be of no avail --" I
bear a charmed life, which must not yield/ To one of woman born"--Macduff reveals the
secret of his birth--" Macduff was from his mother's womb/ Untimely ripp'd". Macbeth now
comes to realize how he has been deceived by the " juggling fiends
".