He who fixed fast and firm the earth that staggered, and set at rest the agitated mountains; who measured out the air's wide middle region and gave the heaven support: He, men, is Indra.
Who slew the Dragon, freed the Seven Rivers, and drove the cattle forth from the cave of Vala; begat the fire between two stones; the despoiler in warriors' battle: He, O men, is Indra.
By whom this universe was made to tremble, who chased away the humbled brood of demons, who, like a gambler gathering his winnings, seized the foe's riches: He, O men, is Indra.
Of whom, the Terrible, they ask, Where is He? or verily they say of him, He is not. He sweeps away, like birds, the foe's possessions. Have faith in him, for He, O men, is Indra.
Stirrer to action of the poor and lowly, of priest, of suppliant who sings his praises; who, fair-faced, favours him who presses Soma with stones made ready: He, O men, is Indra.
He under whose supreme control are horses, all chariots, and the villages, and cattle; he who gave being to the Sun and Morning, who leads the waters: He, O men, is Indra.
To whom two armies cry in close encounter, both enemies, the stronger and the weaker; whom two invoke upon one chariot mounted, each for himself: He, O ye men, is Indra.
Without whose help our people never conquer; whom, battling, they invoke to give them succour; he of whom all this world is but the copy, who shakes things unshakeable: He, O men, is Indra.
He who hath smitten, ere they knew their danger, with his hurled weapon many grievous sinners; who pardons not his boldness who provokes him; who slays the Dasyus: He, O men, is Indra.
He who discovered, in the fortieth autumn, Shambara as he dwelt among the mountains; who slew the Dragon putting forth his vigour, the demon lying there: He, men, is Indra.
Who with seven guiding reins, the Bull, the Mighty, set free the Seven great rivers to flow at pleasure; who, thunder-armed, rent Rauhina in pieces when scaling heaven: He, O ye men, is Indra.
Even the Heaven and Earth bow down before him, before his very breath the mountains tremble. Known as the Soma-drinker, armed with thunder, who wields the bolt: He, O ye men, is Indra.
Who aids with favour him who pours the Soma and him who brews it, sacrificer, singer. Whom prayer exalts, and pouring forth of Soma, and this our gift: He, O ye men, is Indra.
Thou verily art fierce and true who sendest strength to the man who brews and pours libation. So may we evermore, thy friends, O Indra, speak loudly to the synod with our heroes.
measured out the air's wide middle region: Cf. RV 6.69.5: "Ye [Indra and Vishnu] made the firmament of larger compass, and made the regions broad for our existence" (RV 6.69.5).
cave of Vala: a reference to another of Indra's exploits. The demon Vala, closely associated with the Indo-Aryans' aboriginal enemies, had concealed cattle in the mountains; Indra freed them for his followers. Vala is alternately the demon himself and the cave within which the cattle were concealed. More concretely -- and perhaps less heroically -- Indra's release of the cattle represents successful Aryan cattle-raids.
humbled brood of demons: i.e. the "Dasyu color," the Indo-Aryans' adversaries, whom Indra has subdued.
Without whose help our people never conquer: Indra is preeminently the patron deity of the Indo-Aryan warrior-class, presiding over and inspiring their victories:
"Him, verily, the men invoke in combat; risking their lives they make him their protector, when heroes, foe to foe, give up their bodies, fighting, each side, for children and their offspring. Strong God! the folk at need put forth their vigour, striving together in the whirl of battle. When warrior bands encounter one another some in the grapple acquit themselves like Indra." (RV 4.24.3-4).
"Glorify him whose might is all-surpassing, Indra the much-invoked who fights uninjured. Magnify with these songs the never-vanquished, the Strong, the Bull of men, the Mighty Victor. He, Champion, Hero, Warrior, Lord of battles, impetuous, loudly roaring, great destroyer, who whirls the dust on high, alone, oerthrower, hath made all races of mankind his subjects. Thou, thou alone, hast tamed the Dasyus; singly thou hast subdued the people for the Arya." (RV 6.18.1-3).
Shambara: another demon, from whose fortresses Indra rescued (or stole) Soma.
rent Rauhina in pieces: Rauhina may be a drought demon, like Vritra; nothing more is known of him. Elsewhere, however, Indra cast down "the Dasyus, when they fain would climb by magic arts and mount to heaven" (8.14.14).
Heaven and Earth: Dyaus and Prithivi. The former is the common Aryan sky-father who appears, in various forms, in most Indo-European mythologies, notably as Greek Zeus and Roman Jupiter. In the Rig Veda most of his earlier functions have been assumed by Indra.
Rig Veda 2.12. Trans. Ralph T.H. Griffith, The Hymns of the Rig Veda (London, 1889), with some minor modifications to the text. The notes are my own.