The Vedas deal with the three attributes; be thou above these three attributes, O Arjuna; beyond the pairs of opposites, ever steadfast in purity, careless of possessions, full of the Self.
In plain words: Krishna says the Vedas deal with the three qualities of nature (the gunas: goodness, passion and dullness). He tells Arjuna to rise above them and above opposites like hot and cold or praise and blame, to stay pure and steady, not worry about owning things, and rest in his true Self.