Link:- Those, who cast aside the ordinances of scriptures, attain neither perfection nor happiness, nor the Supreme Goal. So what should a man do? The Lord, answers the question, in the next verse.
tasmacchastram pramanam to karyakaryavyavasthitau
jnatva sastravidhanoktam karma kartumiharhasi
Therefore, let the scripture be the authority in determining,what ought to be done and what ought not to be. Having known what is prescribed in the ordinance of scriptures, thou shouldst act accordingly in this world. 24
Tasmacchastraris pramanarim te karyakaryavyavasthitau:-Those, who are attached to their life-breath, do not know what should be done, and what should be refrained from. So, they are specially inclined towards demoniac natum.Therefore, Lord Krsna, advises Arjuna to act according to the ordinance of scripture.
The conduct and words, of saints and great souls, are also based on scripture. So obedience to these, is also obedience to the ordinances of the scripture, because they have become saints and great souls, by following the ordinances of scripture.
In fact, the ordinances of scriptures are the ideas, precepts, and principles, and acts of God-realized souls. The expression 'Sastram pramanam', means that a person, who wants to attain eternal bliss, should readily renounce whatever is prohibited by the scripture, and accept what is ordained by it.
Jnatva sastravidhanoktam karma kartumiharhasi:- People of demoniac nature, do not know, what to do and what to refrain from . So, they do not attain perfection. Lord Krsna says to Arjuna, that he should act, according to ordinances of the scripture, because he possesses the divine nature.
First, Arjuna thought, that sin alone would accrue to him, by killing his kinsmen in the battle. So the Lord declared, "Happy are the Ksatriyas (members of the warrior class), who are called upon to fight, in such a battle that comes of itself, as an open door to heaven". Here, the Lord says that he should discharge his duty, according to the ordinance of the scripture, because it cannot lead him to bondage. An act, which is performed with selfishness and pride, leads to bondage while the action which is performed in an arbitrary way against the ordinance of scriptures, leads to ruin.