In Act III scene 6, Lord tells Lennox how bad things are in Scotland since Macbeth became king.  He informs Lennox, and the audience, that it’s suspected that Macbeth killed Duncan, and that since their father’s murder the two sons has fled.  Malcolm is in England, so MacDuff has gone to try and convince him to return to Scotland and take back his crown.  Lord hopes that if Malcolm returns, things will get better for the people- they will be able to sleep at night and have food on their tables, and have a worthy king to pay homage to.

we may again

Give to our tables meat, sleep to our nights,

Free from our feasts and banquets bloody knives, Do faithful homage and receive free honors. (Line 34-36)
 

The Lord and Lennox are talking about the momentous events of the last few days. The Lord tells Lennox that Malcolm is in hiding in the court of King Edward of England, and that Macduff is on his way to persuade him to come back to Scotland to overthrow Macbeth.. He calls Macbeth a "tyrant" and envisions what would happen if he were overthrown:

[W]ith Him above to ratify the work, we may again 
Give to our tables meat, sleep to our nights,
Free from our feasts and banquets bloody knives, 
Do faithful homage, and receive free honors— 
All which we pine for now.

The fact that Macduff has gone to secure Malcolm, Siward, and Northumberland's support has angered Macbeth so much that he is preparing for war. Clearly, Scotland is in turmoil, and nearing civil war. Shakespeare uses the Lord and Lennox to narrate these complex events to the audience.