diff --git a/src/cli.rs b/src/cli.rs
index 3a04a99..a6f237e 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -47,6 +47,14 @@ enum Commands {
         #[clap(required = true)]
         object: String,
     },
+
+    /// Record changes to the repository
+    #[clap(name = "commit", arg_required_else_help = true)]
+    Commit {
+        /// Use the given <msg> as the commit message
+        #[clap(short, long, value_name = "msg")]
+        message: String,
+    },
 }
 
 pub fn parse() -> anyhow::Result<()> {
@@ -69,6 +77,7 @@ pub fn parse() -> anyhow::Result<()> {
         Commands::CatFile { object } => cat_file(&context, object),
         Commands::WriteTree => write_tree(&context),
         Commands::ReadTree { object } => read_tree(&context, object),
+        Commands::Commit { message } => commit(&context, message),
     };
 }
 
@@ -101,3 +110,8 @@ fn read_tree(context: &data::Context, object: String) -> anyhow::Result<()> {
     context.ensure_init()?;
     context.read_tree(OID(object), &context.work_dir)
 }
+fn commit(context: &data::Context, message: String) -> anyhow::Result<()> {
+    context.ensure_init()?;
+    println!("{}", context.commit(message)?);
+    Ok(())
+}
diff --git a/src/data.rs b/src/data.rs
index 919ecc1..fdf9f67 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -22,6 +22,9 @@ pub enum ObjectType {
 
     #[strum(serialize = "tree")]
     Tree,
+
+    #[strum(serialize = "commit")]
+    Commit,
 }
 
 pub struct Context {
@@ -175,12 +178,32 @@ impl Context {
                     ))?;
                     self.read_tree(oid, &new_path)?;
                 }
+                _ => {
+                    return Err(anyhow::Error::msg(format!(
+                        "unexpected object type '{}' found in '{}' tree",
+                        object_type,
+                        path.display()
+                    )))
+                }
             };
         }
 
         Ok(())
     }
 
+    pub fn commit(&self, message: String) -> anyhow::Result<OID> {
+        self.hash_object(
+            format!(
+                "{}\0{}\n\n{}\n",
+                ObjectType::Tree,
+                self.write_tree(&self.work_dir)?,
+                message
+            )
+            .into_bytes(),
+            ObjectType::Commit,
+        )
+    }
+
     fn is_ignored(&self, path: &PathBuf) -> bool {
         path.starts_with(&self.repo_dir)
             || path.starts_with(&self.work_dir.join("target"))