Aquinas on Prayer in the Eternal Trinity

According to Hans Urs von Balthasar and Adrienne von Speyr, the divine Persons eternally pray to each other. According to Thomas Aquinas, they do not. Thomas allows for ways in which the divine Persons worship, glorify, contemplate, and give thanks to each other. Yet he defines prayer as petition, and he teaches that the divine Persons cannot petition each other—which means that They cannot pray to each other. For Thomas, however, Christ's prayer reveals His eternal sonship, and certain terms in which Thomas casts divine sonship recall those in which he casts prayer. Thomas, therefore, can open up certain avenues towards the conclusion that the petitionary prayer, which is limited to creatures, resembles and is rooted in the Son's eternal sonship.