All four evangelists devote two chapters to the story of the passion and death of Jesus. They refer to the same dramatic events and, although their versions of events are not identical and cannot be put together into one perfectly consistent story from the historical point of view, they essentially agree.
God shows his righteousness and justice by having mercy! This is the great revelation. The apostle says God is “just and justifying,” that is, he is just to himself when he justifies human beings; he is in fact love and mercy, so for that reason he is just to himself—he truly demonstrates who he is—when he has mercy.