How Do Time Stamps in Block Headers Help Secure the Chain?

The timestamp in a block header records the approximate time the block was created. It is used to enforce the network's difficulty adjustment rules, which rely on measuring the time elapsed between 2,016 blocks.

More importantly, it helps prevent miners from "time-warping" the chain by forcing the timestamp to be within a specific, limited range relative to the median of the previous 11 blocks, making it difficult to manipulate the block order for a double-spend.