SB 10.77.19
sri-bhagavan uvaca
vrtha tvam katthase manda
na pasyasy antike ’ntakam
paurusam darsayanti sma
sura na bahu-bhasinah
Translation:
The Supreme Lord said: O dullard, you boast in vain, since you fail to see death standing near you. Real heroes do not talk much but rather show their prowess in action.