diff --git a/lib/diaspora_federation/validators/message_validator.rb b/lib/diaspora_federation/validators/message_validator.rb
index 84650d3..fd1c478 100644
--- a/lib/diaspora_federation/validators/message_validator.rb
+++ b/lib/diaspora_federation/validators/message_validator.rb
@@ -7,6 +7,9 @@ module DiasporaFederation
       rule :author, %i(not_empty diaspora_id)
       rule :guid, :guid
       rule :conversation_guid, :guid
+
+      rule :text, [:not_empty,
+                   length: {maximum: 65_535}]
     end
   end
 end
diff --git a/spec/lib/diaspora_federation/validators/message_validator_spec.rb b/spec/lib/diaspora_federation/validators/message_validator_spec.rb
index 90b5d23..04cf5d0 100644
--- a/spec/lib/diaspora_federation/validators/message_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/message_validator_spec.rb
@@ -19,5 +19,13 @@ module DiasporaFederation
         let(:property) { :conversation_guid }
       end
     end
+
+    describe "#text" do
+      it_behaves_like "a property with a value validation/restriction" do
+        let(:property) { :text }
+        let(:wrong_values) { ["", "a" * 65_536] }
+        let(:correct_values) { ["a" * 65_535] }
+      end
+    end
   end
 end