Albert Barnes Commentary Isaiah 59:2

"but your iniquities have separated between you and your God, and your sins have hid his face from you, so that he will not hear." — Isaiah 59:2 (ASV)

But your iniquities - This refers to the sins that the prophet specified in the previous chapter and proceeds to specify further in this one.

Have separated - The word used here (בדל bâdal) conveys the idea of division, usually by a curtain or a wall (Exodus 26:33; Ezekiel 42:20). Thus the ‘firmament’ (רקיע râqı̂ya‛ — “expanse”) is said to have “divided” or “separated” (מבדיל mab'dîl) the waters from the waters (Genesis 1:6). The idea here is that their sins were like a partition between them and God, so there was no contact between them and him.

And your sins have hid his face from you - Margin, ‘Made him hide.’ The Hebrew word here is in Hiphil, meaning ‘to cause to hide.’ Kimchi and Aben Ezra understand it as causing him to hide his face; Vitringa as hiding his face.

Vitringa says the metaphor is not taken from a man who turns away his face from someone because he does not choose to attend to what is said, but from something that comes between two persons, like a dense cloud, which hides one from the other. According to this, the idea is that their sins had risen up like a thick, dark cloud between them and God, so that they had no clear view of him and no contact with him—as a cloud hides the face of the sun from us. A similar idea occurs in Lamentations 3:44:

Thou hast covered thyself with a cloud,
That our prayers should not pass through.

But it seems more probable to me that the Hiphil signification of the verb is to be retained here. The idea, then, is that their sins had caused Yahweh to hide or turn away his face from their prayers because he was unwilling to hear them when they were so deeply immersed in sin.

Thus, the Septuagint states: ‘On account of your sins he has turned away his face (ἀπέστρεψε τὸ πρόσωπον apestrepse to prosōpon) from you, so that he will not have mercy’ (τοῦ μὴ ἐλεῆσαι tou mē eleēsai).

It is universally true that indulgence in sin causes God to turn away his face and to withhold mercy and compassion. He cannot pardon those who indulge in transgression and who are unwilling to abandon the ways of sin (compare the notes at Isaiah 1:15).