'Conceived and bore' means received essential being and was given manifestation. 'Sarah to Abraham' means from the Lord's Divine spiritual united to His Divine celestial. 'A son' means the Divine Rational. 'In his old age' means when the days had been completed for the human to be cast off. 'At the appointed time' means when the Rational was such that it was receptive. 'As God had spoken to him' means as He had willed.