He paweth in the valley - Margin, "or, His feet dig." The marginal reading is more in accordance with the Hebrew. The reference is to the well known fact of the "pawing" of the horse with his feet, as if he would dig up the ground. The same idea occurs in Virgil, as quoted above:
caavatque
Tellurem, et solido graviter solar ungula cornu.
Also in Apollonius, L. iii. "Argonauticon:"
Ὡς δ ̓ ἀρήΐος ἵππος, ἐελδόμενος πολεμοίο,
Σκαρθμῷ ἐπιχρεμέθων κρούει πέδον.
Hōs d' arēios hippos, eeldomenos polemoio,
Skarthmō epichremethōn krouei pedon.
"As a war-horse, impatient for the battle,
Neighing beats the ground with bis hoofs"
He goeth on to meet the armed men - Margin, "armor." The margin is in accordance with the Hebrew, but still the idea is substantially the same. The horse rushes on furiously against the weapons of war.

He paweth in the valley - יחפרו yachperu, "they dig in the valley," i.e., in his violent galloping, in every pitch of his body, he scoops up sods out of the earth. Virgil has seized this idea also, in his cavat tellurem; "he scoops out the ground." See before.

He (n) paweth in the valley, and rejoiceth in [his] strength: he goeth on to meet the armed men.
(n) He beats with his hoof.

He paweth in the valley,.... Where armies are usually pitched and set in battle army, and especially the cavalry, for which the valley is most convenient; and here the horse is impatient of engaging, cannot stand still, but rises up with his fore feet and paws and prances, and, as the word signifies, digs the earth and makes it hollow, by a continual striking upon it; so generally horses are commonly described in this manner (s);
and rejoiceth in his strength; of which he is sensible, and glories in it; marches to the battle with pride and stateliness, defying, as it were, the enemy, and as if sure of victory, of which he has knowledge when obtained; for Lactantius says (t) of horses, when conquerors they exult, when conquered they grieve; it has its name in the Hebrew language from rejoicing (u);
he goeth on to meet the armed men; without any fear or dread of them, as follows.
(s) "Cavatque tellurem". Virgil. Georgic. l. 3. v. 87. (t) Institut. l. 3. c. 8. (u) "gavisus est". Vid. Buxtorf. in voce

valley--where the battle is joined.
goeth on--goeth forth (Numbers 1:3; Numbers 21:23).

Valley - Battles used to be pitched in valleys, or low grounds, especially horse battles.