Jamieson, Fausset and Brown on 1 Corinthians 15:46

46. afterward--Adam had a soul not necessarily mortal, as it afterwards became by sin, but "a living soul," and destined to live for ever, if he had eaten of the tree of life (Ge 3:22); still his body was but an animal-souled body, not a spiritual body, such as believers shall have; much less was he a "life-giving spirit," as Christ. His soul had the germ of the Spirit, rather than the fulness of it, such as man shall have when restored "body, soul, and spirit," by the second Adam (1Th 5:23). As the first and lower Adam came before the second and heavenly Adam, so the animal-souled body comes first, and must die before it be changed into the spiritual body (that is, that in which the Spirit predominates over the animal soul).