As posted yesterday, ENSLAVED's second album Frost was released 4 August 1993. The song "Yggdrasil" takes it's lyrics from part of the Hávamál poem. The poem is presented in the Codex Regius, an Icelandic collection with many Old Norse poems dating from the late 13th Century. FALKENBACH are another band that used this poem as inspiration.
Here is a detail of the manuscript containing the section of the poem used for "Yggdrasil" (parts 138 - 141). The source is Finnur Jónsson's Facisimile Edition of 1891.
And here is the full page. Relevant part is towards the bottom, starting at II; ending just before the last line.
An English translation of this section by Olive Bray, published in 1908:
I trow I hung on that windy Tree
nine whole days and nights,
stabbed with a spear, offered to Odin,
myself to mine own self given,
high on that Tree of which none hath heard
from what roots it rises to heaven.
None refreshed me ever with food or drink,
I peered right down in the deep;
crying aloud I lifted the Runes
then back I fell from thence.
Nine mighty songs I learned from the great
son of Bale-thorn, Bestla's sire;
I drank a measure of the wondrous Mead,
with the Soulstirrer's drops I was showered.
Ere long I bare fruit, and throve full well,
I grew and waxed in wisdom;
word following word, I found me words,
deed following deed, I wrought deeds.
You can find the complete reproduction of the Codex Regius manuscript here.