This indicates the persecution against the Church set on foot by the nations who still continue in unbelief. But he (Samson) who suffered those things, trusted that there would be a retaliation against those waging this war. But retaliation through what means? First of all, by his betaking himself to the Rock not cognizable to the senses; secondly, by the finding of the jaw-bone of an ass. Now the type of the jaw-bone is the body of Christ.
Source: Fragments from the Lost Writings of Irenaeus (New Advent)