The hebrew word for “Woods” here had a mark indicating that it’s the middle point of the psalms.
It was used by the scribes when copying the scriptures. They used to count each letter they copied and if they detected even a single miswritten letter, they would trash the whole roll. They also read aloud each word before writing and never wrote anything from memory.
Thanks to such meticulous methods, we can be sure that the bible has not been altered.