Humble God

Assume that there's a Humility on the battlefield, and you control Heliod, God of the Sun. Question: Will Heliod be indestructible? But more interestingly: Will your other creatures have vigilance?

(Note that the Oracle text of Humility is: "All creatures lose all abilities and are 1/1." Humility doesn't make anything a creature, nor does it remove any types.)

There are four possible combinations here depending on which one entered the battlefield first, and whether your devotion to white is less than five or not.

The first question depends solely on your devotion to white. If it's less than five, the question is whether Humility removes the ability that makes Heliod a non-creature or not. Since Humility only affects creatures, and Heliod's ability may make it a non-creature, this might at first seem like a chicken-and-egg problem. (If Humility removes the ability, then there's nothing to make it a non-creature, but if the ability makes it a non-creature, then Humility won't affect Heliod.)

However, the seeming problem is resolved thanks to the layering system. Heliod's ability is evaluated in layer 4 (the layer where type setting and removing abilities are evaluated). This happens before evaluating Humility's ability, which is done in layer 6 (the layer where ability adding and removing is evaluated.) Thus Heliod's ability trumps Humility's, and thus if your devotion to white is less than five, Heliod won't be a creature, Humility won't affect it, and it will be indestructible. If your devotion to white is five or more, then Heliod will be a creature and Humility will remove all of its abilities and make it 1/1.

The more complex question is whether your other creatures will have vigilance.

If your devotion to white is less than five, and thus Heliod is not a creature, then it depends on timestamps. This is because there are now two effects that add or remove abilities (and thus are in the same layer.) If Heliod entered before Humility, then your other creatures won't have vigilance, but if Heliod entered after, they will.

Something more complicated happens if your devotion to white is five or more, and thus Heliod is a creature. This is because now the two abilities are dependent: They exist on the same layer, and the existence of one depends on the other. Thus in this case Humility's effect is evaluated first regardless of timestamps, and thus no creatures will have vigilance.