ARMADO Boy, what sign is it when a man of great spirit BOY A great sign, sir, that he will look sad. (1.2.1-3)
Armado thinks Moth will say he's in love. Moping was the classic Elizabethan sign of loving. Armado is hoping to get Moth to admit that he is suffering from love. But Moth doesn't take the bait, so Armado has to wait to talk about it.
ARMADO If drawing my sword against the humor of affection would deliver me from the reprobate thought of it, I would take Desire prisoner and ransom him to any French courtier for a new-devised curtsy. (1.2.59-63)
Armado's a soldier. As a result of his military background, he might think that he can handle love with violence.
ARMADO Adieu, valor; rust, rapier; be still, drum, for your manager is in love. Yea, he loveth. (1.2.181-182)
At the end of this scene Armado develops beyond wanting to stab or ransom his love. He'll put down the weapons and write a love letter instead.
PRINCESS God bless my ladies, are they all in love, That every one her own hath garnishèd With such bedecking ornaments of praise? (2.1.78-80)
None of the ladies admits love, but swoony and love-struck descriptions such as this one give them away.
BOYET If my observation, which very seldom lies, By the heart's still rhetoric disclosèd wi' th' eyes, Deceive me not now, Navarre is infected. (2.1.240-242)
Boyet sniffs out the King's love for the Princess of France. It was common in Elizabethan poetry to describe love as a sickness.
BEROWNE And I forsooth in love! I that have been love's whip (4.3.184)
Berowne is shocked that even he – usually so skeptical – is vulnerable to love.
BOYET I profane my lips on thy foot, my eyes on thy picture, and my heart on thy every part. (4.1.91-93)
Boyet is reading Armado's letter to Jaquenetta. As was the courtly custom, Armado places himself below her. Even laying his eyes on her picture dirties her. (But this doesn't keep him from imagining his heart on "every part.")
KING I heard your guilty rhymes, observed your fashion, Saw sighs reek from you, noted well your passion. 'Ay, me!' says one. 'O Jove!' the other cries. One, her hairs were gold, crystal the other's eyes. (4.3.144-147)
It's funny listening to the King give his friends a hard time, when we figure Berowne must be about to out him. Shakespeare sets up a number of satisfying expectation/fulfillment patterns in the play.
ROSALINE You'll ne'er be friends with him. He killed your sister. KATHARINE He made her melancholy, sad, and heavy, And so she died.(5.2.13-16)
This quote is a little depressing. The mention of Katharine's sister's death by love foreshadows the bad news brought by Marcade.
BOYET Prepare, madam, prepare. Arm, wenches, arm. Encounters mounted are Against your peace. Love doth approach, disguised, Armèd in arguments. You'll be surprised. (5.2.87-90)
Shakespeare uses war imagery to describe love again and again in this play.