Sankaracarya's Vivekachudamani 454

व्याघ्रबुद्ध्या विनिर्मुक्तो बाणः पश्चात्तु गोमतौ ।

न तिष्ठति छिनत्येव लक्ष्यं वेगेन निर्भरम् ॥

vyāghrabuddhyā vinirmukto bāṇaḥ paścāttu gomatau |

na tiṣṭhati chinatyeva lakṣyaṃ vegena nirbharam ||

(Sankaracarya's Vivekachudamani 454)

Thinking it to be a tiger if an arrow is shot at an object, it does not then stop because it turns out to be a cow. It still pierces it with full force.

The bad karmas created by us without getting transcendental knowledge will not diminish our past deeds. We should try to kill the Karmas by learning about the Supreme Lord and Atma. Only by knowing the importance of both, we can get a good result. Otherwise as stated in the sloka, we might target a tiger but will end up with a cow. Anyhow it will pierce the animal which is not the goal of Bhakti.