This is one of the seven statements from Jesus on the cross. It is the darkest moment. He cannot refer to "Father" as He hangs in the place of the sin offering. The Father's fellowship seems distant for the first time in Jesus' life. The Father looks away from the representative of the sin of the world of men. The last Adam, undoing the damage done by the first, triumphing in uninterrupted obedience.
There is the overwhelming sense of Jesus' grief and loneliness in this unmatched situation. Never had a human being experienced such enormous obligation. The paradox of it all staggers us. Priest becomes sacrifice. Teacher becomes lesson. Blessing becomes curse. Righteousness becomes sin.
Remember these verses in 2 Corinthians 5:
20 Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God.
21 For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.
This is a tremendous exchange, His righteousness (perfect law obedience) for our sin. Ridiculous to think of Jesus in the place of the loathsome sinner! Just as ridiculous to think of us in the place of His perfect holiness.
But...it says what it says. Hallelujah! We are forgiven! Repent. Plead for the benefit of this transaction. Close the deal! We are adorned with His robe of righteousness. The Heavenly Father is all smiles. The shadow leaves.
I will conclude with the most beautiful single sentence in the entire New Testament. Look it up.
1 Peter 1: 3-5