Sc. 1, lines 71–104: explain how the state directions and dialogue further the action of the plot. compare the nature of the first murderer’s dialogue to macbeth’s.

This act is devoted to the second great crime of Macbeth's career, the murder of Banquo. The first scene shows us Banquo's suspicions of Macbeth, and Macbeth's fears of Banquo. As a result of the witches' prediction the two old friends are wholly estranged, although outwardly they preserve the forms of a gracious king and a loyal subject. Macbeth's dialogue with the murderers at the close of the scene informs us of the fate that is hanging over Banquo's head. The scene is laid at the palace some time after the coronation of Macbeth. 

1-10. This speech shows Banquo in a wholly different mood from that in which we last saw him. Then he declared that he placed his trust in God and stood opposed to all the designs of treason. Now, although he strongly suspects Macbeth of the treacherous murder of Duncan, he makes no threat of vengeance, but rather broods over the prophecy of the witches that his descendants shall reign, and hopes that this prophecy too may be made good. In other words, he is paltering with evil; he is not yet ready to take any step to hasten the fulfilment of the prediction, but he is content to serve the murderer and usurper in the hope that some profit may come out of it to him and his house. Perhaps if Banquo had lived he would have headed a revolt against Macbeth. This monologue of his at least explains and in part justifies Macbeth's fears.