diff --git a/node/actors/bft/src/leader/replica_commit.rs b/node/actors/bft/src/leader/replica_commit.rs
index ec1a7cad..212c811e 100644
--- a/node/actors/bft/src/leader/replica_commit.rs
+++ b/node/actors/bft/src/leader/replica_commit.rs
@@ -64,6 +64,7 @@ impl StateMachine {
         let message = signed_message.msg;
         let author = &signed_message.key;
 
+        // Check that the message signer is in the validator set.
         consensus
             .validator_set
             .index(author)
diff --git a/node/actors/bft/src/leader/replica_prepare.rs b/node/actors/bft/src/leader/replica_prepare.rs
index e10e958b..c559c7c1 100644
--- a/node/actors/bft/src/leader/replica_prepare.rs
+++ b/node/actors/bft/src/leader/replica_prepare.rs
@@ -76,6 +76,7 @@ impl StateMachine {
         let message = signed_message.msg.clone();
         let author = &signed_message.key;
 
+        // Check that the message signer is in the validator set.
         consensus
             .validator_set
             .index(author)