Correction: I think there might be some confusion. Yes you're right somehow. Labaik actually is Arabic religious term and a call which means something like 'Here I am at your service'. And if you take video's context, meaning of it can be assumed as to march forward.
The lyrics in the description and the translations in the video are a bit wrong in some areas. For example ts not “dihli tak” its “dihli talak” and its not “bharat se” its “wadi se”.
@dranflame_1236 Salam. I am the one who had translated this like a year ago. I listened to the song a couple of times and wrote down the lyrics I could catch. To ensure accuracy, I cross checked from other Urdu lyrical videos of this song, as there were a few words I couldn’t understand due to my not so proficient Urdu vocabulary. For those, I relied on other sources aka videos , which might explain why "Delhi tak" was used instead of "Dihli talak." Or in rare case it could be a minor error from my side, maybe I had overlooked talak with tak? For example lyrics which I couldn't catch were ماؤں کے آنکھوں کو ہم اشکوں سی بھر کر لائیں ہیں and بر سر بازار ہوں ہو پامال جن کی عصمتیں . I apologize for any mistakes.
According to rekhta : یہ پُرانی ہندی کا لفظ ہے۔ ’تک‘ اسی کا مخفف ہے۔ اب یہ لفظ نثر میں نہیں آتا۔ صرف نظم میں مستعمل ہے۔ بعض فصحاء متاخرین کے نزدیک متروک الاستعمال ہے
I think this song might be from Lashkar-e-Taiba, as it seems to be the only one of the Kashmir insurgent groups that has Ghazwa-e-Hind (the idea of reuniting India and Pakistan under Muslim rule) as an objective