Psalms 3:1
מִזְמוֹר לְדָוִד בְּבָרְחוֹ מִפְּנֵי אַבְשָׁלוֹם בְּנוֹ
A song of David, when he fled from his son Absalom.
This Psalm is the first appearance of the familiar introduction "Mizmor l'Dovid" (a song of David). The Talmud in Pesachim (117a) tells us that when a Psalm starts with that phrase, it means that G-d's "spirit" rested on David, inspiring him to sing the song. The converse introductory phrase, "l'Dovid Mizmor" (of David, a song) indicates that David sang the song, which then caused G-d's "spirit" to rest upon him.