How we cite our quotes: (Page.Line) [from Malory, Thomas. Le Morte D'Arthur. Stephen H. A. Shepherd, ed. New York: W.W. Norton and Company, 2004. Print.]
Quote #1
Alle the comyns cryed at ones, "We wille have Arthur unto our kyng. We wille put hym no more in delay, for we all see that it is Goddes wille that he shalle be our kynge – and who that holdeth ageynst it, we wille slee hym." And therwithall they knelyd at ones, both ryche and poure. (11.11-15)
The "commons" are the first people to embrace Arthur as king, which makes the reluctant nobles feel pretty awkward, so they soon follow suit. What's interesting about this is that our narrator is acknowledging the very real power that lower classes have in these sorts of situations. Even though the nobles have all the power, it's the commons that crown Arthur, and set the tone of loyalty for the rest of his reign.
Quote #2
And ther was he sworn unto his lordes and the comyns for to be a true kyng, to stand with true justyce fro thensforth the dayes of this lyf. Also thenne he made alle lordes that helde of the croune to come in and to do servyce as they oughte to doo. (11.20-24)
Ah, a double-edged oath. It's not just the people swearing loyalty to Arthur; he also promises the commons and the nobility to be a "true kyng." Over the course of his reign, Arthur will fulfill this oath by never breaking his word. This in turn helps him demand the absolute loyalty of his knights (and just about everyone else, too).
Quote #3
Than leep in yong Sir Launcelot de Laake, with a lyght herte, and seyde unto Kyng Arthure, "Thoughe my londis marche nygh myne enemyes, yet shall I make myne avow aftir my power that of good men of armys, aftir my bloode, thus many I shall brynge with me: twenty thousand helmys in haubirkes attyred, that shall never fayle you whyles oure lyves lastyth." (116.25-30)
In this scene, Arthur has asked his barons and knights if they'll follow him into battle against Lucius, Emperor of Rome. Launcelot's promise of support is quite longwinded, which emphasizes his loyalty. Maybe that's what makes Arthur so reluctant to go after Lancelot when he learns of his betrayal with Gwenyvere. Launcelot is, after all, the most loyal when it comes to taking down the enemy.