'Hard' in the Bible

Is anything too hard for Jehovah? At the set time I will return unto thee, when the season cometh round, and Sarah shall have a son.

And they journeyed from Beth-el; and there was still some distance to come to Ephrath: and Rachel travailed, and she had hard labor.

And it came to pass, when she was in hard labor, that the midwife said unto her, Fear not; for now thou shalt have another son.