蓄势待发 | xù shì dài fā
On April 13, Xi Jinping gave a speech in Hainan, congratulating Hainan on the 30-year anniversary of its becoming a province and establishment as a special economic zone. Xi directly precedes this chengyu with another that is worth knowing: 三十而立, which refers to the Confucian idiom that by the age of 30 a person should be able to stand on his or her own feet (become established).
To wait (or be prepared) for action after having accumulated power, energy, etc.
经济特区开始，就决心把海南岛好好发展起来。 如果海南岛更好发展起来，中国特色社会主义就更有说服力，更能够 增强人们对中国特色社会主义的信心。