When mine enemies are turned back - Who these enemies were, the psalmist does not say. It is clear, however, as was remarked in the introduction, that the psalm was composed:
(a) in view of a victory which had been achieved over some formidable enemies; and
(b) in view of some dangers still impending from a similar source.
The literal meaning of the passage here is, “In the turning of my enemies back;” that is, in their retreat, defeat, overthrow. So far as the Hebrew form of expression is concerned, this may either refer to what had been done, or to what would be; and may imply either that they had been turned back, or that the psalmist hoped and believed that they would be; for in either case the fact would show the divine perfections, and give occasion for gratitude and praise. The verbs with which this is connected - “they shall fall and perish” - are indeed in the Hebrew, as in our version, in the future tense; but this does not necessarily determine the question whether the psalmist refers to what had occurred or what would occur. His attitude is this: he contemplates his enemies as mighty and formidable; he sees the danger which exists when such enemies surround one; he looks at the interposition of God, and he sees that whenever it occurs it would be followed by this consequence, that they would stumble and fall before him. But while this verse does not determine the question whether he refers to what has been, or to what would be, the subsequent verses Psalms 9:4-6 seem to settle it, where he speaks as if this were already done, and as if God had interposed in a remarkable manner in defeating his foes. I regard this, therefore, as a reflection on what had occurred, and as expressing what was then actually a ground of praise and thanksgiving.
They shall fall and perish - A general statement in view of what had occurred, meaning that this would always be the case.
At thy presence - Before thee; that is, when thou dost manifest thyself. This was the reason why they would stumble and fall, and is equivalent to saying, that “whenever mine enemies are turned back, the reason why they stumble and fall is “thy presence.” It is the interposition of thy power. It is not to be traced to the prowess of man that they thus turn back, and that they fall and perish; it is to be traced to the fact that thou art present - that thou dost interpose.” It is thus an acknowledgment of God as the author of the victory in all cases.