Pope Pius XII
Divino Afflante Spiritu §45
Divino Afflante Spiritu: On Promoting Biblical Studies
45 And if the wished-for solution be slow in coming or does not satisfy us, since perhaps a successful conclusion may be reserved to posterity, let us not wax impatient thereat, seeing that in us also is rightly verified what the Fathers, and especially Augustine, observed in their time viz: God wished difficulties to be scattered through the Sacred Books inspired by Him, in order that we might be urged to read and scrutinize them more intently, and, experiencing in a salutary manner our own limitations, we might be exercised in due submission of mind. No wonder if of one or other question no solution wholly satisfactory will ever be found, since sometimes we have to do with matters obscure in themselves and too remote from our times and our experience; and since exegesis also, like all other most important sciences, has its secrets, which, impenetrable to our minds, by no efforts whatsoever can be unraveled.
Source: Divino Afflante Spiritu (Vatican.va)