Judging Whether a Promise or Threatening Comes From God or Satan

Cases of Conscience, (Pike and Hayward) Case 4: How may a person judge whether a promise or a threatening comes from God, or is brought by Satan to the soul? The occasion of this question is as follows; this person found some of the promises of God's word brought with a peculiar
sweetness and power upon his mind; and these were succeeded by awful threatenings, which appeared to come with equal force. . Now it is of great importance to know whether these come from the Spirit of God, or from Satan.