This was intended to combat both Nestorius's two-persons approach and the monophysite doctrine of Jesus as being so divine that his humanity was overwhelmed. This allowed the Church to affirm that Jesus was truly one person who both participated in the divine Trinitarian "economy" as well as in the human sphere of material being.
In an effort to counter both Nestorius's dualistic theology and the monophysite doctrine, which posited that Jesus's humanity was overwhelmed by his divinity, this approach allowed the Church to affirm Jesus' singular personhood, who simultaneously participated in the divine Trinitarian economy and the human sphere of material being.