Lover and friend hast thou put far from me - That is, Thou hast so afflicted me that they have forsaken me. Those who professed to love me, and whom I loved - those whom I regarded as my friends, and who seemed to be my friends - are now wholly turned away from me, and I am left to suffer alone. See the notes at Psalm 88:8.

And mine acquaintance into darkness - The Septuagint and the Latin Vulgate render this, "my acquaintance from my misery." Luther, "Thou hast caused my friends and neighbors, and my kindred, to separate themselves far from me, on account of such misery." The literal rendering would be, my acquaintances are darkness. This may mean either that they had so turned away that he could not see them, as if they were in the dark; or, that his familiars now - his companions - were dark and dismal objects - gloomy thoughts - sad forebodings. Perhaps the whole might be translated, "Far away from me hast thou put lover and friend - my acquaintances! All is darkness!" That is, When I think of any of them, all is darkness, sadness. My friends are not to be seen. They have vanished. I see no friends; I see only darkness and gloom. All have gone, leaving me alone in this condition of unpitied sorrow! This completes the picture of the suffering man; a man to whom all was dark, and who could find no consolation anywhere - in God; in his friends; in the grave; in the prospect of the future. There are such cases; and it was well that there was one such description in the sacred Scriptures of a good man thus suffering - to show us that when we thus feel, it should not be regarded as proof that we have no piety. Beneath all this, there may be true love to God; beyond all this, there may be a bright world to which the sufferer will come, and where he will forever dwell.

Psalm 88:18 Parallel Commentaries

His Past Work.
His past work was accomplished by Him when he became incarnate. It was finished when He died on Calvary's cross. We have therefore to consider first of all these fundamentals of our faith. I. The Work of the Son of God is foreshadowed and predicted in the Old Testament Scriptures. II. The incarnation of the Son of God. III. His Work on the cross and what has been accomplished by it. I. Through the Old Testament Scriptures, God announced beforehand the work of His Son. This is a great theme and one …
A. C. Gaebelein—The Work Of Christ