God's anger is righteous, but His patience isn't an endless enablement of sin. There's a purpose behind His restraint that ultimately aims for preservation.
The latter part of Isaiah 48:9 states God restrains His anger 'that I may not cut you off.' This is a critical clarification of God's patience.
A Deliberate Holding Back
God's anger is a just response to sin. However, His 'deferring' and 'refraining' are active choices, not passive neglect. He is deliberately holding back the full weight of His judgment.
Preservation, Not Permission
The goal of this restraint is not to allow His people to continue in sin indefinitely. Rather, it is to prevent their ultimate, final destruction. This mercy provides an opportunity for repentance and restoration, even when His people have repeatedly earned His wrath.
It highlights that God's heart longs to preserve His people, even when their actions warrant severe judgment. This patience is a gift, an invitation, and a sign of His enduring covenant faithfulness.