diff --git a/src/main/java/io/zold/api/Wallet.java b/src/main/java/io/zold/api/Wallet.java
index f3cdf4d..682d947 100644
--- a/src/main/java/io/zold/api/Wallet.java
+++ b/src/main/java/io/zold/api/Wallet.java
@@ -227,8 +227,8 @@ public Wallet merge(final Wallet other) throws IOException {
                     new UncheckedText(
                         new FormattedText(
                             "Wallet ID mismatch, ours is %d, theirs is %d",
-                            other.id(),
-                            this.id()
+                            this.id(),
+                            other.id()
                         )
                     ).asString()
                 );
diff --git a/src/test/java/io/zold/api/WalletTest.java b/src/test/java/io/zold/api/WalletTest.java
index 4853fe6..175bac7 100644
--- a/src/test/java/io/zold/api/WalletTest.java
+++ b/src/test/java/io/zold/api/WalletTest.java
@@ -112,7 +112,7 @@ public void doesNotMergeWalletsWithDifferentId() throws IOException {
                 () -> wallet.merge(new Wallet.Fake(123L))
             ).getMessage(),
             Matchers.startsWith(
-                "Wallet ID mismatch, ours is 123, theirs is 5124095577148911"
+                "Wallet ID mismatch, ours is 5124095577148911, theirs is 123"
             )
         );
     }