blocking and protection from color

[blueneverfails]

So the board looks like this, I have a jace, the mind scupltor, and a seagate oracle. He has an ajani's pridemate out and it is a 4/4.
He attacks my jace, and I block with oracle. He then plays an instant spell that gives all white creatures protection from a chosen color. He obv chooses blue. Now I say ok to this and he tells me my jace is dead, and my response to him was that my oracle is still blocking, his Ajani just takes no damage, and he tells me that the spell removes oracle as a blocker from ajani and he gets through. If I know my magic well enough, if he would have played it before I blocked then he would have been safe, but because he did it after blockers it is still blocked and my creature would still take the damage, and the only thing different that would happen if he didnt play the spell is that his ajani will not take the 1 damage from my oracle... Is this correct?

[Julian23]

Protection from block just prevents from declaring units as blockers not from blocking itself.

506.4a Once a creature has been declared as an attacking or blocking creature, spells or abilities that
would have kept that creature from attacking or blocking don’t remove the creature from
combat.

[paeng4983]

Protection from block just prevents from declaring units as blockers not from blocking itself.

506.4a Once a creature has been declared as an attacking or blocking creature, spells or abilities that
would have kept that creature from attacking or blocking don’t remove the creature from
combat.

in other words, it is considered blocked.
your creature (the one blocking) will get x damage
from his creature while his (the attacking one) will
not get any x damage from your blocking creature
because of the protection it gained.

that's how i understood it. im right, right?
:confused:

[Julian23]

correct.