The Divine Presence rests upon a person only in the wake of appropriate preparation. The nature of the preparation determines the nature of the prophecy.

The Divine Presence does not rest on an individual in an atmosphere of sadness, or laziness, or laughter, or frivolity, or idle conversation, but rather in an atmosphere of the joy of a mitzva.

Rabbi Yona says: Jonah son of Amitai was among the festival pilgrims, and only after he participated in the Celebration of the Place of the Water Drawing [Simhat Beit HaSho’eva] did divine inspiration rest on him. This serves to teach you that the Holy Spirit rests only on one with a happy heart.

I call on the heavens and earth to testify: Whether Jew or gentile, man or woman, slave or maidservant: In accordance with the deed he performs, so the Holy Spirit rests on him. (Pesaĥim 117a; Jerusalem Talmud, Sukka 5:1; Tanna deVei Eliyahu Rabba 9)