Learn Farsi: با وجود اینکه دشمن قوی است، این کشور همواره پاینده باد! - Despite the fact that the enemy is strong, may this country always be enduring!

bâd is an old optative (wishing) form of the verb 'to be', translating to 'may it be'. It is considered invariant or 'defective' in modern Farsi, meaning it is frozen in this historical third-person form. Even if the subject were plural, the verb would remain exactly as bâd.

Why do we need in-ke after bâ vojud-e? Can I just say bâ vojud-e došman qavi ast?

You cannot drop in-ke here. The phrase bâ vojud-e translates to 'despite' and must be followed by a noun or noun phrase. Adding in-ke (the fact that) acts as a bridge, turning the entire following subject-verb clause (došman qavi ast) into a noun-like object. To drop in-ke, you would have to change the clause into a simple noun phrase, such as bâ vojud-e došman-e qavi (despite the strong enemy).

What is the difference between hamvâre and the more common word hamiše?

Both mean 'always', but hamvâre is more formal and literary. It carries an elevated, sometimes poetic tone, which makes it a perfect match for a patriotic, formal wish like this one. In everyday spoken Farsi, you would stick to hamiše.

How is the word pâyande constructed?

It is formed by taking the present stem of pâyidan (to last or to remain) and adding the suffix -ande. This suffix creates an active participle, which is an adjective describing the doer of the action. Therefore, literally means 'that which lasts' or 'enduring'.