The Cross.

The Cross has Proven that when man gave his worst to God, God thought Higher and changed it to Give His Best for all men.

Crucifixion

The worst event to befall God became the Best event for all men because by His Crucifixion, now all men will attain Salvation by Him in their respective times; but it doesn’t end there since it will also be the cause of Salvation for the whole World too.

That’s why John the apostle writes in all truth (this comparison):

“He (Lord Jesus Christ) is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world.” (1 John 2:2)