You forget that many times something is such a "given" it won't be mentioned explicitly.
Such as someone dying for the Faith going to heaven -- many writers wouldn't waste their ink defending something so obvious.
That is why we Catholics need a living, teaching magisterium, to explain away these written difficulties in Scripture, the Fathers, writings of the Saints, etc. -- to explain their proper meaning.
The protestant way -- private interpretation -- doesn't work. It leads to sects, and sects of sects because each man has his own opinion that he is attached to.
Matthew