Macduff is referring to the murder of King Duncan, which has been revealed to the public when he uses the word "murther" (murder) and "broke ope" (exposed) to describe the crime. This revelation is a turning point in the play as Macduff begins to suspect Macbeth's guilt and seeks justice for the heinous act.
The act of murder has been revealed.
It means that "murder has become unrestrained" i.e. killings are mounting up and seemingly out of control.
He was testing Macduff to see if he genuinely had the interest of Scotland at heart. When Malcolm says "He hath not touched you yet" (IV, iii, 14) it means that he suspects Macduff is in league with Macbeth to take him prisoner and kill him. Malcolm then makes up all his vices to make sure that Macduff wants a good king and not just Malcolm. When Macduff responds that with his vices, Malcolm would make a terrible kind, Malcolm responds that he made the vices up and he knows that Macduff has Scotland's best interests at heart.
The "life of the building" is the life of Duncan in Macduff's line in Act II Scene 3, "Most sacrilegious murder hath broke ope the Lord's anointed temple and stole thence the life o' the building." Macduff is comparing the king to a sacred temple which someone has broken into. And what has been stolen? The king's life.
You hath to do it because it hath to be done. See the Related Question in modern English to find out why.
Hath-Set was created in 1940.
It means "if you have goals in life you have purpose."
Hath is an archaic word, third person singular present of 'have'
This means "if you have goals in life you have a purpose."
Music Hath Charms was created in 1935.
Friar Laurence says this line in "Romeo and Juliet." He is referring to how fate has intervened and prevented their plans from succeeding.
thy god hath lent thee , by these angels he hath sent the, Respite--respite and nepenthe from thy memories