Putana wanted to serve Krsna by feeding Krsna with her breast, but the purpose was the breast was poison, so Krsna would suck the milk and He would die. There is a different motive. But still, Krsna is so kind that He thought that "This rascal Putana, she wanted to kill Me, but she does not know that I am not a person to be killed, but still, although the motive was to kill Me, but she has served Me to suck her breast. I have drunk her milk. So she is My mother. So she is My mother. Never mind she came with a motive."
So this is the Krsna consciousness benefit. Of course, we should not have any more… Kamsa. Kamsa, just like. He was simply thinking of Krsna. He was Krsna conscious fully, always thinking of Krsna. But the motive was to kill. So still, Kamsa got liberation because he was constantly thinking of Krsna. But ac… That is not bhakti. Bhakti is the same thinking of Krsna — favorably. Anukulyena krsnanusilanam [Cc. Madhya 19.167]. That is bhakti. To think of Krsna as enemy, that is not required. One may think, but a devotee, how can he think of Krsna as enemy? He thinks of Krsna as friend, as son, as master, as lover. A devotee thinks like that, whereas a demon or an enemy of Krsna, he's always thinking of… This is the difference between demon and devotee. Demon is thinking how to wipe out, how to banish Krsna, how to kill Krsna. They don't want Krsna. That is demonic.
>>> Ref. VedaBase => Bhagavad-gita 2.39 — London, September 12, 1973