NOTES for Psa 31
The psalmist compares the Lord to a secure fortress whose walls shelter from enemy attacks. But fortress walls cannot protect someone who is in no hurry to enter the fortress. There is only one way to enter the fortress and receive its protection: by accepting the Lord and entering into covenant with Him. He is always ready to protect us, but when we move away from Him, we ourselves reject His protection.
Enemies press in from every side and constantly plot evil, but in the face of their threats we can hope in the Lord’s mercy. Yet evil comes not only from external enemies: the psalmist acknowledges that his strength has failed because of his own sins. It is therefore no accident that enemies oppress us; through our sins we strengthen them and bring them upon ourselves.
But even in such sorrowful circumstances, the psalmist continues to hope in the Lord, the reliable protector who hears the prayer even of one who seems rejected in his own eyes. Even in this condition, the one who prays continues to cry out because he remains faithful. And this means that he has already entered within the fortress walls.