My beloved, obedient as you have always been,
not only when I am present but all the more now when I am absent,
work out your salvation with fear and trembling.
For God is the one who, for his good purpose,
works in you both to desire and to work.
In the British comedy film, Bedazzled, the Temptor complains to Stanley Moon, a hapless lover, that God pries into everything. There is no privacy! He reminds us that the measure of one's integrity is how we act when no one is watching.
Saint Paul had announced the Gospel to Ephesus, survived a riot. and then left town. He then expected them to, "Be obedient as you have always been." He had, in effect, acted like Jesus who announced the Gospel, verified it with his passion, death, and resurrection, and then disappeared into the clouds.
Despite a few rare appearances after his Ascension, Jesus seemed in the view of the foolish largely absent. He had left the critical work of saving the world to a group of fishermen, tax collectors, zealots, and the Pharisee Paul. So the Apostle followed the same pattern when he evangelized and departed Ephesus. They had heard the Gospel; they were on their own.
But, as the Holy Spirit had more than filled in the absence of Jesus, so it satisfied the Ephesian longing for the Apostle's return. They had only to work out their salvation with fear and trembling.
Deus absconditus is what we call our complaint. God seems to be missing; He has absconded. In fact, God rarely appears visually in the Old and New Testaments; He visits Adam and Eve; and later, Abraham and Sarah. And Jesus is God in the flesh; revealed publicly for a very few years.