it's maybe from a letter called "To Lu Dingyi" (《致陆定一》) written by Mao Zedong (毛泽东) in 1964. i'm not sure. it's said that the original sentence was "古为今用，洋为中用", which means "to use the past to serve the present, to use the foreign to serve the chinese".

"古为今用" gǔ wéi jīn yòng Come From《致陆定一》(To Lu Dingyi)by Comrade Mao Zedong. originally is 古为今用，洋为中用.In English is: Make the past serve the present and foreign things serve China. Example:①Take our policies on literature and art for example. Comrade Mao Zedong has said it is necessary to make the past serve the present, to make foreign things serve China, to let a hundred flowers bloom and to weed through the old to bring forth the new. ②With regard to the rich cultural legacies left over from China's history of several thousand years, we should select the essence and discard the dross therefrom, and carry forward and develop them in line with the spirit of the times in order to make the past serve the present. You can see this site :http://baike.baidu.com/view/82171.htm(all Chinese╭（╯_╰）╭) awesome...You can speak so many languages....Cool.......I can't add you......so upset...........anyway....Nice to meet U......Have a nice day..~~~~

i think it is "古为今用"，cuz past=古 it means using what you have leared from a incident that happened in the past, which is really far away from now, maybe 100years ago to deal with the trouble or problem or just a nomal thing you meet today. in a word, it means using the knowledge known in the ancients times to guide what happen nowadays but sorry for have no idea about where it comes from, it is just a idiom.

是“古为今用”吧。 gǔ wéi jīn yòng it seems u have known what's the meaning. 古为今用：弘扬古代的精粹，为当今所用。simply to say:learn something good from the past,and used for nowdays. 不知道出自哪里，会用就行，呵呵...你可以上百度看看。