This was Baasha, who slew Nadab, the son of Jeroboam, and wiped out every member of the house of Jeroboam (ch. 15:28, 29).
Even now.
Judgment would not wait long. The day of doom had already dawned, and anyone who read the signs of the times might know that the times were evil. The thought is similar to that expressed by Jesus, “I am come to send fire on the earth; and what will I, if it be already kindled?” (Luke 12:49).