Another parable put he forth unto them, saying,The kingdom of heaven is like to a grain of mustard seed which a man took, and sowed in his field: Which indeed is the least of all seeds: but when it isgrown, it is the greatest among herbs, and becometh a tree, so that the birds of the air come and lodge in the branches thereof.

-Bible (NewTestament)
St Matthew13:31^2.

And Jesus said unto them,Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.

-Bible (NewTestament)
St Matthew17:20.

We wove a web in childhood, A web of sunny air; We dug a spring in infancy Of water pure and fair; We sowed in youth a mustard seed, We cut an almond rod; We are now grown up to riper ageö Are they withered in the sod?

-Bronte«  , Charlotte
  'We Wove a Web in Childhood'.

They know on the Continent that European football without the English islike a hot dog without themustard.

-Charlton, Sir Bobby (Robert)
  Quoted in Peter Ball and Phil Shaw The Book of Football Quotations (1989). There was at the time a Europeanban inforce against English clubs.