The truth is sometimes seen, but rarely heard: on the fewest of occasions does it arrive in its elemental purity, especially if it has travelled far, for then it is always soiled by what has happened on the road: for feeling tinges with her colors all that she touches, sometimes happily, sometimes unhappily: she always leaves some kind of mark.

[La verdad ordinariamente se ve, extravagantemente se oye; raras veces llega en su elemento puro, y menos cuando viene de lejos; siempre trae algo de mixta, de los afectos por donde pasa; tiñe de sus colores la pasión cuanto toca, ya odiosa, ya favorable. Tira siempre a impresionar.]

Baltasar Gracián y Morales (1601-1658) Spanish Jesuit priest, writer, philosopher

The Art of Worldly Wisdom [Oráculo Manual y Arte de Prudencia], § 80 (1647) [tr. Fischer (1937)]
    (Source)

(Source (Spanish)). Alternate translation:

Commonly truth is seen, but it is extraordinary to hear it. It seldom comes pure to our ears, especially when it come from a far. For then it takes some tincture of the passions that it meets by the way. It pleases or displeases, according to the colours that passion or interest give it, which aim always at prepossessing.
[Flesher ed. (1685)]

The truth is generally seen, rarely heard; seldom she comes in elemental purity, especially from afar; there is always some admixture of the moods of those through whom she has passed. The passions tinge her with their colors wherever they touch her, sometimes favorably, sometimes the reverse.
[tr. Jacobs (1892)]

Truth is more often seen than heard. Seldom does it reach us unalloyed, even less so when it comes from afar. It is always blended with the emotions it has passed through. Emotion taints everything it touches, making it odious or favorable. It tries always to impress us one way or another.
[tr. Maurer (1992)]