Romans 6:4

Therefore we are--rather, "were" (it being a past act, completed at once). buried with him, by baptism into death--(The comma we have placed after "him" will show what the sense is. It is not, "By baptism we are buried with Him into death," which makes no sense at all; but, "By baptism with Him into death we are buried with Him"; in other words, "By the same baptism which publicly enters us into His death, we are made partakers of His burial also"). To leave a dead body unburied is represented, alike in heathen authors as in Scripture, as the greatest indignity (Rev 11:8-9). It was fitting, therefore, that Christ, after "dying for our sins according to the Scriptures," should "descend into the lower parts of the earth" (Eph 4:9). As this was the last and lowest step of His humiliation, so it was the honorable dissolution of His last link of connection with that life which He laid down for us; and we, in being "buried with Him by our baptism into His death," have by this public act severed our last link of connection with that whole sinful condition and life which Christ brought to an end in His death. that like as Christ was raised from the dead by the glory of the Father--that is, by such a forth-putting of the Father's power as was the effulgence of His whole glory. even so we also--as risen to a new life with Him.

— Jamieson-Fausset-Brown Commentary (public domain)