Juvenal was among those who condemned the heresy and affirmed the doctrine of the union of two natures in Jesus Christ, the divine and the human, without separation and without mixture.
[3]: 248 Whereas Juvenal had previously hoped to extend Jerusalem's jurisdiction to include Roman Arabia and Phoenicia, negotiations with Archbishop Maximus of Antioch at Chalcedon resulted in approval of oversight over all of Palestine but no further.
[3]: 248 [9] Theodosius reportedly filled Jerusalem with blood, then raised a military company to punish other rivals in the region like Severianus, Bishop of Scythopolis, whom he brutally executed in 452 or 453.
[7][9] Juvenal likely had monastic roots as he attended a monastery in the Kedron valley and was known for his strong support of Palestinian monasticism; many of the men he ordained to the ranks of the clergy were local monks.
He also did much to promote liturgical development in Jerusalem and its environs; it was during his episcopate that the Feast of the Theotokos on 15 August was introduced and churches dedicated to Mary began to be built in the province.
[3]: 247 The extent of the oversight granted to the jurisdiction at Chalcedon was both a significant expansion on the precedent established at Nicea and was supra-Metropolitan in scale.