The Pakistanis cannot fight an organised army, never mind "big army like India". The reason Pakistan invested so heavily in "non-state actors" like Taliban, LeT, JuD etc. is because the army needed scapegoats to bind India in one place while they plan strategic moves. Unfortunately Pakistan did never calculate about a certain OBL and the effects of 9/11. The Taliban felt betrayed by Pakistan siding with US and now you have a civil war in Pakistan which is unlikely to end because the rebels have emotional and ideological support from conservative Pakistani society.
The Pakistani army has been a flop show in their zarb e azb, yes the Pakistanis are pounding furiously at rebel cities with bombardment and air power. But the Pakistanis forgot what they had been shouting to USA all along, indiscriminate bombing only adds numbers to rebel cause. To kill 10 militants Pakistan bombards an entire village killing 10 militants and 100 civilians with them. 10 years has passed but the end of Pakistani civil war is still not in sight. One commander dies, another one comes up to take his place. More and more ground has been lost by Pakistan in the war and the casualties simply keep mounting.
A "professional" army that cannot defeat taliban in their own backyard cannot make such lofty claims.