Four pillars of spiritual life — and Krishna sets them all aside. Not by study of the Vedas. Not by penance. Not by charity. Not by ritual sacrifice. None of these, alone or together, can produce the vision that Arjuna just received.
This is not a rejection of those practices. A farmer needs a plough, seeds, water, and sunlight. But none of those things, by themselves, make the crop grow. Something else is at work — the life force in the seed, the timing of the season. Similarly, study and discipline prepare the ground. But the vision itself comes from a different source.
Krishna is clearing the stage. In the very next shloka, He will name what that source is. These four negations — no Vedas, no penance, no charity, no sacrifice — are not a dead end. They are a doorway. They tell the listener: stop looking in those directions. Look here instead.