Questions I have had about the Bible recently...

[Gwaithmir]

So, I have studied the Bible a bit recently, and I posted some questions about it on various Internet forums. So, I thought I might share it with you guys...

Why does Psalm 137:4 ("How will we sing the song of the Lord in a foreign land?") mean? Was there some common superstition back then that religious songs must not be sung in a foreign land? How does that make any sense? The most sensible answer I received is that "song of the Lord" is supposed to be a joyous song, and that it is inappropriate to sing it while in exile.

got to remember alot of the psalms were songs of joy and thanks giving. others were laments and prayer recorded during captivity. for instance the book of kings 1 and 2 are a period of where the jews are captured sold into slavery, repent as a people and god restores them a generation goes by and the cycle repeats. 
in this case you have a lament, that is saying how can we sing songs of worship and praise while we are here in a foreign land as slaves (where the people do not support or love God as they do.) the passage asks how can we sing of the joy of the lord when nothing in the foreign land is of god. we know this to be the indisputable case as the rest of the passage frames it out to be so:
Psalm 137
1 By the rivers of Babylon we sat and wept
    when we remembered Zion.
2 There on the poplars
    we hung our harps,
3 for there our captors asked us for songs,
    our tormentors demanded songs of joy;
    they said, “Sing us one of the songs of Zion!”
4 How can we sing the songs of the Lord
    while in a foreign land?
5 If I forget you, Jerusalem,
    may my right hand forget its skill.
6 May my tongue cling to the roof of my mouth
    if I do not remember you,
if I do not consider Jerusalem
    my highest joy.

---

and i can not help you with any of the vulgate passages as i study the koine/hebrew bible.

Perhaps it was politically incorrect at the time to pray to your own god in a foreign land. Some extant ancient correspondence shows the writers praying to strange gods while in countries other than their own. There might have also been a belief that gods only held sway in the countries in which they were chiefly worshiped.

Henotheism - Wikipedia