If God is not just, God is not good. If God does not respond justly to the unrighteous decisions of his creatures, then God cannot be holy, good or righteous. In the same way earthly judges cannot be good while perverting justice in their courtrooms, the perfect Judge cannot be perfect if he ignores sin. His perfect love does not negate, invalidate or nullify the perfection of his justice. Without justice there is an eternal imbalance, a nagging discrepancy, and a lack of divine equilibrium in the universe that cannot be disregarded.
This reality is our predicament and the quandary of the human race. The gospel of course is the solution. But realize God’s love does not repeal God’s justice. Instead, God’s love provided a judicial solution. The whole point of Christ’s crucifixion was the exacting of rigorous justice motivated by extreme love. If love were enough to solve our problem and maintain divine perfection, there would have been no costly incarnation and no crushing crucifixion.
But of course there was. The solution was extravagantly provided because God is love, and it was necessary because God is just.