diff --git a/modules/swagger-codegen/src/main/resources/ruby/api.mustache b/modules/swagger-codegen/src/main/resources/ruby/api.mustache
index ca3e2c153cb..e69765707d2 100644
--- a/modules/swagger-codegen/src/main/resources/ruby/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/ruby/api.mustache
@@ -82,7 +82,7 @@ module {{moduleName}}
       {{/minimum}}
       {{#pattern}}
       if {{^required}}!opts[:'{{{paramName}}}'].nil? && {{/required}}{{#required}}{{{paramName}}}{{/required}}{{^required}}opts[:'{{{paramName}}}']{{/required}} !~ Regexp.new({{{pattern}}})
-        fail ArgumentError, 'invalid value for "{{#required}}{{{paramName}}}{{/required}}{{^required}}opts[:"{{{paramName}}}"]{{/required}}" when calling {{classname}}.{{operationId}}, must conform to the pattern {{{pattern}}}.'
+        fail ArgumentError, "invalid value for '{{#required}}{{{paramName}}}{{/required}}{{^required}}opts[:\"{{{paramName}}}\"]{{/required}}' when calling {{classname}}.{{operationId}}, must conform to the pattern {{{pattern}}}."
       end
 
       {{/pattern}}
diff --git a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
index b83b97d2db5..5a0398b6bc9 100644
--- a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
+++ b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
@@ -154,7 +154,7 @@ module Petstore
       # verify the required parameter 'pattern_without_delimiter' is set
       fail ArgumentError, "Missing the required parameter 'pattern_without_delimiter' when calling FakeApi.test_endpoint_parameters" if pattern_without_delimiter.nil?
       if pattern_without_delimiter !~ Regexp.new(/^[A-Z].*/)
-        fail ArgumentError, 'invalid value for "pattern_without_delimiter" when calling FakeApi.test_endpoint_parameters, must conform to the pattern /^[A-Z].*/.'
+        fail ArgumentError, "invalid value for 'pattern_without_delimiter' when calling FakeApi.test_endpoint_parameters, must conform to the pattern /^[A-Z].*/."
       end
 
       # verify the required parameter 'byte' is set
@@ -180,7 +180,7 @@ module Petstore
       end
 
       if !opts[:'string'].nil? && opts[:'string'] !~ Regexp.new(/[a-z]/i)
-        fail ArgumentError, 'invalid value for "opts[:"string"]" when calling FakeApi.test_endpoint_parameters, must conform to the pattern /[a-z]/i.'
+        fail ArgumentError, "invalid value for 'opts[:\"string\"]' when calling FakeApi.test_endpoint_parameters, must conform to the pattern /[a-z]/i."
       end
 
       if !opts[:'password'].nil? && opts[:'password'].to_s.length > 64