paśhyaitāṁ pāṇḍu-putrāṇām āchārya mahatīṁ chamūm
vyūḍhāṁ drupada-putreṇa tava śhiṣhyeṇa dhīmatā
paśhya — behold;
etām — this;
pāṇḍu-putrāṇām — of the sons of Pandu;
āchārya — respected teacher;
mahatīm — mighty;
chamūm — army;
vyūḍhām — arrayed in a military formation;
drupada-putreṇa — son of Drupad, Dhrishtadyumna;
tava — by your;
śhiṣhyeṇa — disciple;
dhī-matā — intelligent
In this verse, Duryodhana is speaking to his teacher, Dronacarya. He is asking Dronacarya to look at the large army that has been gathered by the Pandavas, who are the sons of Pandu. This army is arranged in a very skilled way, and it was organized by Dhrishtadyumna, who is the son of Drupada. Dhrishtadyumna learned military strategy from Dronacarya himself!
Duryodhana is pointing out this army for a couple of reasons. First, he wants to highlight Dronacarya's past mistake. Dronacarya and King Drupada, Dhrishtadyumna's father, had a conflict. Because the two were enemies, Drupada performed a special ritual to have a son who would defeat Dronacarya. That son turned out to be Dhrishtadyumna, who ended up learning everything he knew about warfare from Dronacarya.
Now, Duryodhana is trying to remind Dronacarya of this situation. He wants to show that Dhrishtadyumna has taken what Dronacarya taught him and used it to create a powerful army for the Pandavas. By doing this, Duryodhana is really making a jab at Dronacarya. He is suggesting that if Dronacarya had been more cautious with whom he taught his skills, perhaps his own student, Dhrishtadyumna, wouldn't be such a strong opponent now.
The idea behind Duryodhana's words is twofold: First, he wants Dronacarya to realize how his previous kindness in teaching Dhrishtadyumna has come back to challenge him in battle. Second, Duryodhana wants to encourage Dronacarya not to be lenient or overly kind in the battle against the Pandavas. Duryodhana fears that if Dronacarya goes easy on his former students, who he cares for deeply, then it might lead to their defeat.
In simpler terms, Duryodhana is using this moment to remind his teacher to be fierce and serious in this fight. He does not want Dronacarya's feelings to get in the way of what is needed to win the battle.