Then Ehud went out to the porch; he shut the doors of the upper room behind him and locked them. Judges 3:23

Ancient locks consisted of a wooden slide drawn into place by a string and fastened there by teeth or catches.

The lock commonly used in Egypt or Palestine is a long hollow piece of wood fixed in the door which slid back and forth. A hole is made for it in the door post. When it is pushed into the hole small bolts made of iron wire fell into holes made for them in the top of the lock. The lock was placed on the inside of the door near the lock, and a hole was made in the door near the lock through which the hand could pass and a key inserted. This explains Song of Songs 5:4- "My lover thrust his hand through the latch opening (put in his hand by the hole of the door, KJV); my heart began to pound for him."

Some locks were very large and heavy.