Albert Barnes Commentary Psalms 9:9

"Jehovah also will be a high tower for the oppressed, A high tower in times of trouble;" — Psalms 9:9 (ASV)

The Lord also will be a refuge – Margin: a high place. The margin expresses the more exact sense of the Hebrew word משׂגב (miśgâb). It properly means height or altitude; then a high place, rock, or crag.

Because such locations are inaccessible to an enemy and were sought in times of danger as places of secure retreat, the term comes to mean a place of security and refuge (Psalms 18:2; Psalms 46:7, 11; Psalms 48:3; Psalms 59:9, 17; Psalms 94:22).

The declaration here is equivalent to what is so often said: that God is a refuge, a rock, a high tower, a defense. This means that those referred to might find safety in Him. See the notes at Psalms 18:2.

For the oppressed – literally, for those who are crushed or broken; hence, the dejected, afflicted, or unhappy – דך (dak) – from דכך (dākak): to beat small, to break in pieces, to crush. The allusion here is to those who are wronged or downtrodden, to the victims of tyranny and injustice. Such people may look to God to vindicate them and their cause, and they will not look in vain. Sooner or later He will manifest Himself as their protector and their helper. See Psalms 9:12.

A refuge in times of trouble – This applies not only to the oppressed but to all those who are in trouble. Compare Psalms 46:1. That is, all such individuals may come to Him with the assurance that He will be ready to pity them in their sorrows and to deliver them. The psalmist had found this to be true in his own case, and he infers that it would be so in all cases, and that this might be regarded as the general character of God.