When i read about horrific massacres against hindus during 1400 years of islamic invasion, i wonder if there is a bhagwan or does he really care about his devotees.Why he didnt punish muslims, where is karma ?. Here is one such example http://www.ikashmir.net/exodus/index.html
Yes, definitely, God really cares for us. It is said in the Bhagavad Gita.
ananyāś cintayanto māḿ ye janāḥ paryupāsate |
teṣāḿ nityābhiyuktānāḿ yoga-kṣemaḿ vahāmy aham ||9.22||
But those who always worship Me with exclusive devotion, meditating on My transcendental form—to them I carry what they lack, and I preserve what they have.
He declared that he will care about the people who worships him.
Now, the question why Muslim invaders not punished for their massacres can't be answered by facts because we don't know what happened to them in their personal life after they did these invasions and massacres is not well documented. But they will be served their Karma. But we don't know when and how.
God does not actively run the universe. It is primordial Nature, God’s shakti (power) which does everything.
Resorting to Prakrti, Nature, which is My own Power, I send forth again and again this multitude of beings that are without any freedom, owing to Nature's sway over them.
These activities do not in any way bind Me, because I remain detached like one unconcerned in their midst.
Under My direction and control, Nature brings out this mighty universe of living and non-living beings. Thus does the wheel of this world revolve.
God remains normally as a spectator. God only helps those who do spiritual practice (Gita 9.22). Others will have to live according to their karma.