Here the means something like 'since' or 'in that, and the subject of 'had given' is 'X '. Thus we can know nothing about the number or gender of the X. The verse makes clever use of this ambiguity, for who or what is it who has given the speaker such a temperament? It could be, most obviously, one of the antecedent nouns in the first line, either 'martyrdom' itself, or 'destiny'. Or it could be considered to be some unexpressed but implied entity like 'God' or 'He' or 'Nature'. Then in the second line, we're also left to interpret the meaning of that bowing of the head. Complete submission to fate? Worship, as Bekhud Dihlavi suggests? Readiness or even eagerness for slaughter, so that the bowed head will encourage the sword to do its work? It would also arguably be possible to read as 'world'-- 'I saw the world as a sword' (or equally, 'I saw the sword as a world'). But this feels like overreaching. It is after all possible to overread poets, even Ghalib. The curved shape of the sword itself might also suggest a reciprocal bowing of the head: graphics/sword.jpg