According to Baidu Encyclopedia, looking back and looking back comes from 1992 Lv Xiaomin's Poem Selected Poems of Canaan. Composed by Lv Xiaomin. So this song was originally sung by Lv Xiaomin.
Some of the lyrics are: look back/look at the road you have traveled/how much you have paid/whether your time has been wasted/when you left home/determined to go with the Lord/whether you still have some nostalgia/whether you are mature today.