This hymn, attributed to the lineage of Vishvamitra and is in the Gayatri metre. It's probably the most translated and familiar Vedic hmyn, being the very 1st hymn in the oldest of the Vedas - the Rig Veda. Yet, as many online sources as I have seen, there seem to be as many translations... As I said with 'Vande Mataram,' poetic licence is often taken while translating. Add to that the fact that Vedic Sanskrit differs from Classical Sanskrit! I'm sure there are much more beautiful translations you could find but here's what the grammar says:
अग्निमीळे पुरोहितं यज्ञस्य देवं ऋत्विजं |
होतारं रत्नधातमम् ||
vigraha from the padapāṭha:
अग्निम् ईळे पुरोहितं यज्ञस्य देवं ऋत्विजं होतारं रत्नधातमम्
I venerate Agni, the priest (lit. who is placed on the seat of honour/in the East), divine ministrant of the sacrifice, bestower of treasure, par excellence.
अग्निम् - [अग्नि को ] accusative singular of Agni, Vedic god of fire. As you would expect, since the verb is in 1st person, 'I venerate', the rest of the verse is mostly in the accusative. agnim, hotaaram, ritvijam etc.
ईळे - [I] venerate; 1st person singular from root ईड् (2A) - to implore, to extoll
पुरोहितम् - [पुरोहित को] priest, placed on the seat in the East [पुरः+हित] or placed ahead; accusative singular
यज्ञस्य - of the sacrifice; genitive singular of यज्ञ masc. noun
देवम् - divine, if taken as an adjective; [देव को] if read as acc. singular of deva, masc. noun
ऋत्विजम् - priest; accusative singular
होतारम् - priest who recites hymns of the Rig Veda
रत्नधातमम् - superlative of 'bestower of treasure/wealth' रत्न+धाता; accusative bahuvrihi compound, refering to Agni.
I shall continue with the translation of the rest of the hymn verse by verse. Feedback and comments welcome!