What is the ruling regarding a father who is not just among his children?

Justice among children is an obligation according to many scholars, and abandoning it is forbidden and an act of injustice, based on the Prophet's (peace be upon him) saying: "I do not bear witness to injustice," and his saying: "Fear Allah and be just among your children." And based on the view of obligation, the unjust father must repent to Allah, do good in what remains of his life, and seek forgiveness from those of his children whom he has wronged.