Cong Fang

“The atonement is an absolute consequent necessity. By that, we mean that God was not obligated to redeem His people, but once He had chosen to do so (by His own will and for HIs good pleasure) the atonement became absolutely necessary. It was consequent to His decree, but necessary. That also means that there is no other way for God to be both just and the justifier of sinners.” (fredtgreco)

https://www.puritanboard.com/threads/the-necessity-of-the-atonement.12390/