diff --git a/app/models/user.rb b/app/models/user.rb
index de4f37c2..6ae0b3cc 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -150,6 +150,9 @@ class User < ApplicationRecord
   end
 
   def comment(answer, content)
+    raise Errors::CommentingSelfBlockedOther if self.blocking?(answer.user)
+    raise Errors::CommentingOtherBlockedSelf if answer.user.blocking?(self)
+
     Comment.create!(user: self, answer: answer, content: content)
   end
 
diff --git a/lib/errors.rb b/lib/errors.rb
index ab7a8b7a..a56cb778 100644
--- a/lib/errors.rb
+++ b/lib/errors.rb
@@ -73,5 +73,11 @@ module Errors
 
   class AnsweringSelfBlockedOther < SelfBlockedOther
   end
+
+  class CommentingSelfBlockedOther < SelfBlockedOther
+  end
+
+  class CommentingOtherBlockedSelf < OtherBlockedSelf
+  end
   # endregion
 end