That's totally random. As a paladin, me being stupid and sentimental I used my resurrect scroll up to save the died Horsemen in the dragon fight during training, thinking I'd soon find another (my first game). I only found Resurrect in Elinia, which is late in the game...
With my Mage, I found Resurrect on the freedom islands (the eldest Cook brother sells it, if you help him to inherit his dad's fortune).
As said, it is totally random.