Jerome : (Verse 10) However, he said, 'Returning, I will come to you at this time and in this hour, and Sarah will have a son.' For 'hour,' we read 'life' in Hebrew, so that the order or sense is: I will return to you in the time of life, as if he were saying, if I live, if life accompanies me. This, however, is anthropopathically expressed, like other things. — Hebrew Questions on Genesis