How to understand“Sleep that knits up the ravell'd sleeve of care”？？？
Macbeth, Act II, Scene II

Macbeth:

Methought I heard a voice cry 'Sleep no more!
Macbeth does murder sleep', the innocent sleep,
Sleep that knits up the ravell'd sleeve of care,
The death of each day's life, sore labour's bath,
Balm of hurt minds, great nature's second course,
Chief nourisher in life's feast....

Question

How to understand“Sleep that knits up the ravell'd sleeve of care”？？？
Macbeth, Act II, Scene II
 

Macbeth:

Methought I heard a voice cry 'Sleep no more!
Macbeth does murder sleep', the innocent sleep,
Sleep that knits up the ravell'd sleeve of care,
The death of each day's life, sore labour's bath,
Balm of hurt minds, great nature's second course,
Chief nourisher in life's feast....

Answer

Here Shakepeare means that sleep 'knits up' or secures what has become confused or tangled in our lives.(something that is ravelled is tangled confused or knotted)  Sleep brings loose ends together. It lets things settle down and smooths out what was giving us problems before we went to sleep.