Psalm 13:1
How long wilt thou forget me, O LORD? for ever? how long wilt thou hide thy face from me?
How long wilt thou forget me, O LORD? for ever?.... When God does not immediately deliver his people from their enemies, or help them out of an affliction; when he does not discover his love, communicate his grace, apply the blessings and promises of his covenant as usual; and when he does not visit them in his usual manner, and so frequently as he has formerly done, they are ready to conclude he has forgotten them; and sometimes this continues long, and then they fear they are forgotten for ever; and this they cannot bear, and therefore expostulate with God in a querulous manner, as the psalmist does here; but this is to be understood not in reality, but in their own apprehension, and in the opinion of their enemies; God never does nor can forget his people; oblivion does not fall upon him with respect to common persons and things; and much less with respect to his own dear children, for whom a special book of remembrance is written;
See Gill on "Psalms 9:18";
How long wilt thou hide thy face from me? his love, and the manifestation of it, from his person; his gracious presence, the light of his smiling countenance, which sometimes God hides or withdraws from his people by way of resentment of their unbecoming carriage to him; and which is very distressing to them, for they are apt to imagine it is in wrath and hot displeasure, when he still loves them, and will with everlasting kindness have mercy on them; see Isaiah 8:17. The Targum renders it, "the glory of thy face".