Dic: give of

• Retired people are often willing to give of their time to help with community projects.
• He GIVE OF his free time to help the club.
• She really gave of her time to help.
• They give of themselves to improve the quality of education.

1. give of something: phrasal verb | if you give of yourself, your time, your money etc, you do things for other people without expecting anything in return:

2. give of: Contribute without expecting anything in return, usually time or money

3. To devote or contribute

... http://www.ldoceonline.com/dictionary/give_1

... http://www.usingenglish.com/reference/phrasal-verbs/give+of.html

... http://www.thefreedictionary.com/give