Antiphona 1

'O admirabile commercium' (O wondrous exchange) expresses the patristic doctrine of the 'marvelous exchange' (admirabile commercium) central to soteriology: God became man so that man might become God. The phrase 'Creator generis humani' (Creator of the human race) identifies the child as the pre-existent Logos through whom all things were made (John 1:3). The participle 'animatum' (ensouled) affirms against Apollinarian heresy that Christ assumed complete human nature including a rational soul. At Lauds on Marian feasts, this antiphon places Mary's maternity within cosmic redemption - she bore not merely a human baby but the Creator himself entering creation.