【英文译文】It is better to safeguard what you have already accomplished than to crave for exploits of the future. It is better to guard against further mistakes than to waste time regretting past ones.
It is better to preserve the exploits already in hand than to attempt the ones not yet achieved. Likewise, it is better to prevent mistakes in the future than to regret the ones you made in the past.
Rather than seek new achievements, try to maintain old ones; regret over past mistakes, but also try to avoid future ones.