He that will not when he may, when he will he shall have nay

Here ‘nay’ means ‘a refusal’. This proverb could apply to a certain Mr Lambert. One afternoon he was telephoned by a friend who offered him a free ticket for the theatre that evening. Mr Lambert did not want to go, so he declined with thanks. Half an hour later he changed his mind and rand his somebody else.

See also:

• Opportunity seldom knocks twice