In John 16:7 Jesus says " Nevertheless I tell you the Truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you, but if I depart, I will send Him unto you."
Here we see Jesus tell the disciples and us today, that in order for our Helper, the Holy Spirit to have access to this world ruled by evil, that He (Jesus) had to go to the Cross and be crucified to fulfill the Plan of God; that we have a Comforter for our souls and spirits.
He did not say that He was going to remove evil from this world. But the Father's plan was to give us a Comforter and reveal our King Jesus to us.
God knows us and the evil in us and He knows the perfect way to bring about what He wills. Because of His Holiness He works within those parameters of Holy Law that He has set out.
We will see when the Great Judgement comes that God has never unlawfully dealt with us. We will see that He is dealing with evil in the most pure and holy legal way, and we deserved under the Law to have the consequences we were dealt in this life, because of our unbelief.
Evil will have no loophole to wiggle through at the Great Judgement to come, where every inhabitant of Heaven will see God's Holiness, Power & Might, Pure Law, Perfect Judgement, and we will understand that He has All The Power to do as He pleases and that He is a Good and Pure God full of Light and Love and Mighty in Power.
Every knee will bow whether it wants to or not. The Power coming from Him will send those to their knees who would not normally bow to anyone.
The Comforter was released to reveal Jesus to us. He works tirelessly in and through believers, and miracously as needed to draw unbelievers to Christ and to encourage and teach believers. He takes our prayers to the Throne Room and Mercy Seat of God to make sure they are delivered in the Holy language to Jesus.
Praise the Lord!