diff --git a/lib/sinon/spy-formatters.js b/lib/sinon/spy-formatters.js
index f39b2a9d6..58685453d 100644
--- a/lib/sinon/spy-formatters.js
+++ b/lib/sinon/spy-formatters.js
@@ -72,29 +72,29 @@ module.exports = {
                 j < calledArgs.length || j < expectedArgs.length;
                 ++j
             ) {
-                if (calledArgs[j]) {
-                    calledArgs[j] = quoteStringValue(calledArgs[j]);
+                var calledArg = calledArgs[j];
+                var expectedArg = expectedArgs[j];
+                if (calledArg) {
+                    calledArg = quoteStringValue(calledArg);
                 }
 
-                if (expectedArgs[j]) {
-                    expectedArgs[j] = quoteStringValue(expectedArgs[j]);
+                if (expectedArg) {
+                    expectedArg = quoteStringValue(expectedArg);
                 }
 
                 message += "\n";
 
                 var calledArgMessage =
-                    j < calledArgs.length ? sinonFormat(calledArgs[j]) : "";
-                if (match.isMatcher(expectedArgs[j])) {
+                    j < calledArgs.length ? sinonFormat(calledArg) : "";
+                if (match.isMatcher(expectedArg)) {
                     message += colorSinonMatchText(
-                        expectedArgs[j],
-                        calledArgs[j],
+                        expectedArg,
+                        calledArg,
                         calledArgMessage
                     );
                 } else {
                     var expectedArgMessage =
-                        j < expectedArgs.length
-                            ? sinonFormat(expectedArgs[j])
-                            : "";
+                        j < expectedArgs.length ? sinonFormat(expectedArg) : "";
                     var diff = jsDiff.diffJson(
                         calledArgMessage,
                         expectedArgMessage
diff --git a/test/assert-test.js b/test/assert-test.js
index 95e49d8ad..7fcd282e5 100644
--- a/test/assert-test.js
+++ b/test/assert-test.js
@@ -2172,7 +2172,7 @@ describe("assert", function () {
                     "expected doSomething to be called once and with exact arguments \n" +
                     "Call 1:\n"
                 }${color.red("4")}\n${color.red("3")}\n${color.red(
-                    inspect(JSON.stringify('"bob"'))
+                    inspect('"bob"')
                 )}\nCall 2:`
             );
         });
@@ -2188,6 +2188,18 @@ describe("assert", function () {
             );
         });
 
+        it("assert.calledWith message is idempotent", function () {
+            this.obj.doSomething("hey");
+
+            this.message("calledWith", this.obj.doSomething, "");
+            this.message("calledWith", this.obj.doSomething, "");
+            this.message("calledWith", this.obj.doSomething, "");
+            assert.contains(
+                this.message("calledWith", this.obj.doSomething, ""),
+                '"hey"'
+            );
+        });
+
         it("assert.alwaysCalledWithExactly exception message", function () {
             this.obj.doSomething(1, 3, "hey");
             this.obj.doSomething(1, 3);