勿失己心
[wù shī jĭ xīn]
This translates into 'don't lose your heart/mind'. Here, mind doesn't just refer to logic and intellect but rather one's true self and original intents - do not let them become lost or distorted amid confusion and interference caused by external matters. It reminds us to stay true to ourselves and adhere to our hearts, even if the path through life may encounter distractions or changes. It's both a reminder and an affirmation of self-value.