The main line of the song i.e. "Tumhi ho bandhu, sakha tumhi" is actully the Hindi translation of the second line of the Sanskrit Shloka which is as follows:
"tvam-ev mata, cha pita tvam-ev
tvam-ev bandhu, cha sakha tvam-ev
tvam-ev vidya, dravidam tvam-ev
tvam-ev sarvam mum dev dev."