Isaiah has a vision, and in his vision, he sees the holiness of God. The holiness of God has ramifications displayed at the cross of Jesus.
Psalm 88 is the darkest and saddest psalm in all the Psalter. In this song of lament, Heman the psalmist pleads with God for deliverance from his suffering, questions God in the midst of his suffering, and clings to God despite his suffering. The psalm ends in darkness, where Heman seemingly lived with no resolution or apparent hope. This darkness points to the suffering and death that Jesus Christ would taste for us, from which the hope of the kingdom to come will bring ultimate salvation!