How is the Old Testament fulfilled in the suffering of Christ?

Luther:

David, speaking as a prophet, declares in Psalm 8, in a unique way – and that for all people on earth – the Person of Christ, and says: ‘What is man, that Thou art mindful of him? And the son of man, that Thou visitest him?’ In this way he describes here the incomprehensible depth of Christ’s humiliation. Because he sees Christ in His deepest humiliation and suffering, namely that He is mocked, scourged, spit upon, crowned with thorns and crucified.

Paul also speaks about this humiliation: ‘He humbled Himself, and became obedient unto death, even the death of the cross’ (cf. Philippians 2:8). And we read in the Psalm: ‘But I am a worm, and no man; a reproach of men, and despised of the people’ (cf. Psalms 22:6). In this humiliation nobody saw Him anymore as a man [but as a worm]. Everyone who passed, shook his head and said: ‘How [terribly] has God this man accursed that he hangs now at the cross [or: wood]’ (cf. Deuteronomy 21:23; Galatians 3:13).

It is as Isaiah says: ‘As many were astonied at Thee; His visage was so marred more than any man, and His form more than the sons of men.’ Idem: ‘He hath no form nor comeliness; and when we shall see Him, there is no beauty that we should desire Him. He is despised and rejected of men; a Man of sorrows, and acquainted with grief: and we hid as it were our faces from Him; He was despised, and we esteemed Him not.’ (cf. Isaiah 52 and 53). He indeed says in Psalm 22: ‘But I am a worm, and no man; a reproach of men, and despised of the people’.

Now, David marvels about this and says: ‘How is it possible, or how will one be able to believe it that God will think of this forsaken and dismal human: that He will accept this son of man, who dies so miserably on the cross? Should he – spit on, jeered at and defamed by everyone – be the sweetest Child and the beloved of God? How foolishly does God act?

Would He, God’s Son, be Lord and Ruler, Whose name is excellent in all countries and Who is thanked in heaven? (cf. Psalm 8:1, 2). After all, He hangs on the cross and is being held for a derision and curse of men! David says this all in great wonder, as if he would say: ‘The whole world is thinking that God has forgotten this Man and that He does not accept this Son of men. But: ‘The stone which the builders refused, is become the head stone of the corner. This is the LORD’S doing; it is marvellous in our eyes’ (cf. Psalms 118:22, 23; 1 Peter 2:7).