And Moses sent to call Dathan and Abiram, the sons of Eliab: which said, We will not come up:

Wesley's Notes

16:12 Dathan and Abiram - To treat with them and give them, as he had done Korah and his company, a timely admonition. Come up - To Moses's tabernacle, whither the people used to go up for judgment. Men are said in scripture phrase to go up to places of judgment.

Jamieson-Fausset-Brown Bible Commentary

12-14. Moses sent to call Dathan and Abiram-in a separate interview, the ground of their mutiny being different; for while Korah murmured against the exclusive appropriation of the priesthood to Aaron and his family, they were opposed to the supremacy of Moses in civil power. They refused to obey the summons; and their refusal was grounded on the plausible pretext that their stay in the desert was prolonged for some secret and selfish purposes of the leader, who was conducting them like blind men wherever it suited him.

Matthew Henry's Concise Commentary

16:12-15 Moses summoned Dathan and Abiram to bring their complaints; but they would not obey. They bring very false charges against Moses. Those often fall under the heaviest censures, who in truth deserve the highest praise. Moses, though the meekest man, yet, finding God reproached in him, was very wroth; he could not bear to see the people ruining themselves. He appeals to God as to his own integrity. He bade them appear with Aaron next morning, at the time of offering the morning incense. Korah undertook thus to appear. Proud ambitious men, while projecting their own advancement, often hurry on their own shameful fall.