He 'dedicated' [='devoted'] his life/time 'to' helping the poor. = He 'dedicated himself to' helping the poor. [=he used his time, energy, etc., to help the poor]
We have a 'dedicated' phone line for our computer. [=a phone line that we use only for our computer]
They are a group of highly 'dedicated' [='committed', 'enthusiastic'] individuals.
(..) so that they'd join you in mocking him. If you saw him while you ate, you couldn't finish your meal. Then the lawyer. You had to secretly thank me for that. This is a man who dedicated his life... to making money by lying with every breath he could muster to keep... murderers and rapists... (..)1995 Se7en