'Appointed Time' in the Bible

And God said, "Let there be lights in the vaulted dome of heaven {to separate day from night}, and let them be as signs and for appointed times, and for days and years,

But my covenant will I establish with Isaac, whom Sarah shall bear to thee at this appointed time in the next year.

And Jehovah saith unto Abraham, 'Why is this? Sarah hath laughed, saying, Is it true really -- I bear -- and I am aged? Is any thing too wonderful for Jehovah? at the appointed time I return unto thee, about the time of life, and Sarah hath a son.'

And Sarah conceived, and bore Abraham a son in his old age, at the appointed time of which God had spoken to him.