And one should never be excessively credulous.

एकाग्रः स्यादविवृतो नित्यं विवरदर्शकः।

राजन्नित्यं सपत्नेषु नित्योद्विग्नः समाचरेत्॥

ईन्दिस्चे स्प्रूचे ३८३५ महाभारते

ekāgraḥ syādavivṛto nityaṁ vivaradarśakaḥ|

rājannityaṁ sapatneṣu nityodvignaḥ samācaret||

īndisce sprūce 3835 mahābhārate

The guidelines for a safe and sane lifestyle for all, and especially for people doing duties for the State .. The advice comes as an advise by a sage minister to the King

A sensible and diligent person should ever maintain a lifestyle with thoughts and action well oriented and in sync with a sharp and pointed mind, he should take care not to expose or reveal his plans, agenda or even thought process to others, especially those who are competitors and those who are not well wishers, he should never fail to see through the machinations, the secret plannings, the hidden agenda hatched by others. 

And one should never be excessively credulous. 

Reasonable fear and anxiety about the activities of the enemies, competitors and unfriendly people should be entertained and one should always take constant care to safeguard himself against such unfriendly activities

K V ANANTHANARAYANAN

राजन्, oh king पुरुषः a man, a sensible person नित्यं on a constant, day to day basis, as a matter of regular lifestyle एकाग्रः, very sharp and oriented in his thoughts and action अविवृतः should never expose, reveal his thoughts and plans to others, especially competitors and unfriendly peopeople विवर दर्शकः ever keen to see through the concealed secret intentions and hidden agenda of others स्यात् should be सपत्नेषु in the case of enemies नित्योद्विघ्नः he should be circumspect, he should entertain necesssary fear and caustion समाचरेत् behave act