Do what is good. Next sentence: Don't ask the end of the song.
It means to choose something useful to do, regardless of the result.
"Choose the good and do it" comes from Wei Zhi's "Ten Steps Can't Stop the Dilemma" in the Tang Dynasty: "This directly means the words of Du Jian, how about those who choose the good and do it?"
Wei Zhi (that is, Prime Minister Wei Zhi):
Wei Zhi (February 11th, 58-643) was born in Xiaquyang County. ? An outstanding politician, thinker, writer and historian in the early years of Tang Dynasty. Wei Zhi took part in the Wagang Uprising in his early years and followed Wei Gong Shi Biao, but he could not be reused. In the first year of Wude (618), he surrendered to the Tang Dynasty and was responsible for persuading the British public Li Ji. After that, he granted the Prince a horse wash, assisted Prince Li Jiancheng, and offered suggestions to pacify Liu Heita and Shandong.
After the change of Xuanwu Gate, it came under the command of Li Shimin, Emperor Taizong of Tang Dynasty. At first, it was awarded to Zuo Cheng, a doctor of advice and an official of proofreading, to appease Hebei. Move to the secretary's supervisor again, participate in the pre-political affairs, and revise ancient books. After moving to the middle school, he was appointed as the Duke of Julu County and was responsible for the provincial affairs. Tired of giving Dr. Zuo Guanglu and the prince a surname, he was awarded the title of Zheng Guogong.
he spoke out many times and advocated kingliness. He once put forward that "listening to others is bright, but listening to others is dark", "Be prepared for danger in times of peace, and refrain from extravagance and frugality", and advocated "collecting taxes sparingly", "paying attention to taxes", "ruling the world with leniency" and so on, which had a very beneficial influence on Li Shimin's actions and administration, and assisted Li Shimin in creating "the rule of chastity".
in the seventeenth year of Zhenguan (643), Wei Zhi died at the age of 64. Posthumous title was awarded the title of "Wen Zhen". ? Then he was ranked fourth in the "Twenty-four Heroes of Lingyange". Wei Zhi once participated in the compilation of the preface to A Collection of Books and Sui Shu, and the general introduction to Liang Shu, Chen Shu and Qi Shu, etc., and his remarks were mostly found in Zhenguan dignitaries. The collection of official documents of Wei Zheng and the collection of poems of Wei Zhenggong are preserved today.