ichorclaw Myr attacks, then we go to declare blockers, and it gets blocked by a wolfir silverheart . Then apostle’s blessing is cast on the myr giving it green pro.
The myr will do damage to the silverheart and myr's effect will trigger but it will still be blocked with no return damage from the silverheart.
If the owner of the myr wanted to prevent blocking they needed to cast the blessing prior to declare blockers stage. This correct or am I missing something?