At first pass, the saying can be taken to mean:

" Strike blow for Justice"

For messianic leaders, the phrase was heaven-sent. Even the famous female Empress Wu Zetian used it since she considered herself an incarnation of the future Buddha. And perhaps she was, given her impressive achievements in reorganizing government, ridding corruption from her ranks, and initiating edicts that raised the living standards of the lower classes.

However, when she assumed power, she inherited a relatively stable situation. During the other dynasties, commoners were in much worse shape, which made them ripe for exploitation by would-be messiahs.

The other segment of Chinese society used it was the Jianghu Youxia, wandering heroes. Unlike their selfish counterparts in the Jianghu, these men and women traveled the countryside, "striking blows for justice" while practicing their code of conduct. Those who practiced the ideal of ethical martial behavior had such skill that they could extend forgiveness, compassion, and mercy to their enemies.

Furthermore, the favors given to the common people were given without obligation. A task was done because it was needed, and the Youxia possessed sufficient Qigong to complete it. This brings us to another level of meaning contained within the phrase.