For our light affliction, which is but for a moment, is working for us a far more exceeding and eternal weight of glory, while we do not look at the things which are seen, but at the things which are not seen. For the things which are seen are temporary, but the things which are not seen are eternal. (2 Corinthians 4:17-18)
Looking for the things not seen—which are eternal—is how many of the Church Fathers read the scriptures. The readily seen things are the literal readings of the text which might be obvious to anyone. This level of understanding requires no faith or love as even a nonbeliever can comprehend it. The ‘unseen’ things, which are eternal, require us to look even deeper into the text, beyond the literal, to find that which is the mystery which God has hidden in Scripture. For in that which is not readily seen by the naked eye, they hoped to see God in what God was choosing to reveal to us in His love. This looking requires faith, hope, wisdom and love. The ‘unseen’ is made visible by God in His love to those who are capable of seeing.
Clement of Alexandria points out that God reveals Himself through mystery to help make us into seekers, those who choose to be Christ’s disciples and who wish to commune with God.
The meaning of Scripture is hidden for many reasons: first, that we might be seekers (zetetikoi), and ever on the watch to discover the words of salvation; secondly, because it was not fitting that all should know this meaning, for fear they might come to harm through misunderstanding what was said by the spirit for their salvation’ (Strom VI, 15:126,1). (GOSPEL MESSAGE AND HELLENISTIC CULTURE, p 253)
Because God’s mystery revealed is divine, it is possible for some to misunderstand it. God reveals to each of us according to our abilities. So, it is possible that to protect some from falling into error, that it is better for them that certain aspects of God’s revelation remain a mystery. God will give them to know what they need to know, but there may remain some things beyond their comprehension. This is OK because God in His love reveals to each what they need to know for their salvation.