He who undertakes too much seldom succeeds.

Related:

• He who undertakes too much seldom succeeds. --
  Dutch...
• He who is outside his door already has a hard part of his journey behind him.
  Dutch...
• He who suffers much will know much.
  Greek...
• Who begins too much accomplishes little. --
  German...
• He who talks too much commits
  a sin...
• He who considers too much will perform
  little. ...
• A handfull of patience is worth a bushel of brains.
  Dutch...
• A little pot boils easily.
  Dutch...
• Little pots soon run over.
  Dutch...