釋禪波羅蜜次第法門 2.102

2.102

既無法利，又失世樂，覺其過已，當急棄之。悔者若掉，無悔則不成蓋。何以故？掉時未在緣中，故後欲入定時，大悔前所作，憂惱覆心，故名為蓋。

Since one has neither the benefits of the Dharma nor worldly joy, having recognized its fault, one must promptly discard it. As for regret: if there is restlessness without regret, it does not constitute a hindrance. Why is this? While restless, one is not yet engaged with the object [of meditation]; therefore, later, when wishing to enter concentration, one greatly regrets what was done before, and sorrow and distress veil the mind; hence it is called a hindrance.