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.
(..) no one would dare stand up to him until you. They oppose him, yet they do nothing. There are some politicians who have dedicated their lives to Rome. One man above all. If I can arrange it, will you meet him? Do you not understand? I may die in this cell tonight, (..)2000 Gladiator