Given his devious, treacherous behavior later on in the play, it may come as something of a surprise to see Macbeth praised for his heroism and courage in act 1, scene 2.
And yet there is no doubt that Macbeth has acquitted himself magnificently on the field of battle, leading Scottish forces to victory against Irish invaders led by the renegade Macdonwald. During the battle, Macbeth killed Macdonwald in a particularly gruesome fashion, slicing him almost in half before sticking his severed head on the battlements as a warning to others.
As well as having to fight an invading force of Irishmen, Macbeth also had to contend with a Norwegian army assisted by the treacherous Thane of Cawdor. But the enemy proved no match for the Scots and were soundly beaten.
After the battle, the treacherous Thane of Cawdor was captured and executed on Duncan's orders. As a reward for his daring exploits, King Duncan awards the now vacant title of Thane of Cawdor to Macbeth as a reward for his daring exploits.
There's little doubt that the picture of Macbeth presented to us in act 1, scene 2 is a very positive one indeed. He comes across as a brave, noble warrior, prepared to do and die for his king and country. Macbeth is highly respected by other men, most notably his king, who lavishes praise and honors upon his most valiant soldier. There's certainly no sign as yet that the new Thane of Cawdor will turn out to be even more of a traitor than the last one.