The words "the arrogant" and "the wicked" are nominal adjectives that can be translated with nouns. The verb for the second phrase may be supplied from the first. Alternate translation: "I said to the arrogant people ... and I said to the wicked people" (See: [[rc://en/ta/man/translate/figs-nominaladj]])
Asaph speaks of wicked people as if they were animals with horns on their heads, stretching their necks and holding their heads high to frighten other animals. Alternate translation: "Do not be confident" or "Do not boast about how strong you are" (See: [[rc://en/ta/man/translate/figs-metaphor]])