Can I cast that on my white creature and say protection from white? Will the spell work ok on my creature?
Yes, you can cast Gods Willing on a white creature and then choose white as it resolves.
Yes. By the time Gods Willing grants protection, it doesn't do anything anymore, that protection cares about. It doesn't deal Damage, it doesn't Enchant/equip, it doesn't Block. And the Targeting check for the spell is already past (it happened right at the start of the spell resolving) and won't be done again. (Remember the acronym DEBT for what protection helps against)
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"Simple questions" usually need rather complex answers, while complex questions often come down to no more than a simple "yes" or "no".
What part of hayaku ikee did you not understand?
Who truly runs this city? Look to the sky on hallowed days, and see whose sigil is stamped clearly onto the heavens. - Vuliev of the Ghost Council
We have no need for military might. We wield two of the sharpest swords ever forged: Faith in our left hand, Wealth in our right. - Vuliev of the Ghost Council
Options will cost you, but a lack of them will cost you even more.
The wizard who reads a thousand books is powerful. The wizard who memorizes a thousand books is insane.
A single dedicated mind can bring about the greatest destruction. That, or goblins - goblins work too.
Of course you should fight fire with fire. You should fight everything with fire. - Jaya Ballard, task mage
He unmakes the world in his own image.
Who's the crazy one now? - Torgle, mountaintop boatmaker
Fair? At what point in our negotiations did you convince yourself my goal was to be fair?
After breaking free from the Riptide Project, the slivers quickly adapted to life on Otaria - much to the dismay of life on Otaria.
Choices are rarely as simple as they seem.