It is only when a man does not commit a sin in thought, deed or word in respect of any living creatures, it is then that he attains to the purity of Brahma.
यदा न कुरुते पापं सर्वभूतेषु कर्हिचित्। कर्मणा मनसा वाचा ब्रह्म सम्पद्यते तदा॥