Divine Right of Kings
Regicide (killing of a king/queen) was seen as an appalling crime because it was a crime against God. The Jacobeans believed in the Divine Right of Kings - that God anointed (chose) the monarch. Murdering a king disrupted the natural order and would have been condemned by an audience to whom Guy Fawkes' Gunpowder Plot was a recent memory.
Witchcraft & superstition
The Jacobean audience were highly superstitious and would have believed in the power of the supernatural. The witches were viewed by Christian Jacobean audiences as powerful, malicious figures, closely associated with the devil.
Women in Jacobean society
The Jacobean audience believed that women were natural nurturers, meek and subservient. Lady Macbeth's decision to unsex herself to fulfil her desire for power would have been very shocking to a Jacobean audience who would find this completely unnatural. Jacobean society was a patriarchal one which meant that men held authority over their wives.
Holinshed's Chronicles
Shakespeare uses an old source, Holinshed's Chronicles, as a basis for 'Macbeth'. In the original story, Duncan was an imperfect king and Banquo was an accomplice in the murder of Duncan. Shakespeare deliberately changes both in his version to create a saint-like king and an innocent Banquo, to flatter James I (who claimed Banquo was his ancestor).
Greek tragedy convention
Shakespeare uses the Greek tragedy convention of a tragic and noble hero who has a fatal flaw/weakness - a hamartia - which leads to his downfall. Macbeth's hamartia is his ambition. Shakespeare also uses the classic five act structure of the ancient Greeks which always ended with resolution.
Predetermination vs self-determination
The Jacobeans believed in predetermination but Shakespeare was interested in the idea of self-determination, the way in which people control their own lives. This exploration is evident in the examination of the witches' role in the play - do they control the characters or do the characters have autonomy over their own decisions?
Shakespearean staging
Shakespearean theatre would have been limited in terms of props and special effects, so the hideous vocabulary of moments like 'gouts of blood' works hard to help the audience imagine the violent murder.
Military manhood
The Jacobean era was one of political and social unrest. Military strength was seen as an important part of being a man, as was loyalty to the king. In Jacobean times, kings were expected to be able to lead armies at time of war.