Verse 28

तस्मादनन्तसिद्ध्यर्थं शाश्वताय सुखाय च ।तज्जये यत्नमातिष्ठ कष्टयापि हि चेष्टया

In plain words

Therefore, for the sake of unending siddhi, and for lasting happiness, hold fast to the effort of conquering him, even through hardship and struggle.