Ephesians 4:9

‘Now this “he ascended”, what does it indicate but that he also descended into the lower parts of the earth.'

Paul then takes the opportunity for a small digression in order to exalt Christ. He points out that for this Giver to have ascended there must first have been a descent, for the Psalmist was speaking of God. ‘The lower parts of the earth' may simply indicate human birth (see Psalms 139:15 where it may mean the womb or the Adamic birth from the dust of the ground) or the ground, possibly but not necessarily with some element of humiliation (Isaiah 44:23; Psalms 71:20), and it would seem that Paul has in mind the incarnation. He is basically saying, ‘He Who was God descended'. Some however would see it as meaning His descent into the grave (Psalms 63:9). There are no grounds here for suggesting that the raising of men from Hades is meant. Such a suggestion is pure speculation.