A quote that indicates Hamlet's tragic flaw that appears later in Shakespeare's Hamlet is spoken in Act 4.4.31-32. Hamlet has just witnessed Fortinbras's army on its way to Poland to capture a piece of worthless land. Two thousand men and 20,000 ducats will be the cost of just beginning the attack, all for something so worthless. Hamlet sees this as a rebuke of his failure to kill Claudius, and says:
How all occasions do inform against me,
And spur my dull revenge! ...
... I do not know
Why yet I live to say 'This thing's to do;'
Sith I have cause and will and strength and means
To do't. ...
Hamlet says "all occasions," not just the occasion of seeing the Norwegian army. He sums up other events in the play that he has also interpreted as rebukes: the player's speech concerning Hecuba, his refusal to kill Claudius while Claudius was praying, the fact that the ghost had to appear to him a second time because Hamlet had not yet done his job though he has "will and strength and means."
All occasions do, indeed, inform against Hamlet's delay. At least that's how he sees it in this scene.
Thus conscience does make cowards of us all,
And thus the native hue of resolution
Is sicklied o'er with the pale cast of thought,
And enterprises of great pitch and moment
With this regard their currents turn awry,
And lose the name of action
The above quotation from Hamlet's famous "to be or not to be" soliloquy in Act III Sc.1 encapsulates Hamlet's 'tragic flaw' and his moral dilemma.
Hamlet's 'tragic flaw' of course is 'hestation' - he is aware that his Uncle Claudius has murdered his father and has usurped the throne. Now, all that he has to do is to quickly avenge the evil deeds of his uncle. But Hamlet is hampered by his scrupulous conscience, which is governed by religious precepts of Protestantism and which prevent him from believing in the rightness of avenging his father's murder (Fortinbras eventually shames him into acting though he never answers his own questions to his satisfaction). His conscience and religion prevent him from acting swiftly causing to debate at length with himself the questions the regicide and command to revenge cause.