Jeremiah 23:25

The Lord was aware that the prophets were falsely claiming to have had dreams in which they received messages from Him (cf. Zechariah 10:2).

Dreams were one way that Yahweh communicated His revelations to people in ancient times (cf. Genesis 28:10-17; Genesis 37:5-11; Genesis 40; Genesis 41:1-45; Numbers 12:6-8; 1 Kings 3:5-15; Daniel 2; Daniel 4:4-27; Daniel 7; Joel 2:28; Zechariah 1:7 to Zechariah 6:8). The pagans also viewed dreams as a way the gods communicated with them. Consequently it was possible to claim a revelation in a dream and to obtain an audience. The person who received a revelation from Yahweh in a dream knew it, but it was very difficult for someone else to know if the dream that a prophet claimed as divine really came from Yahweh.