23 Heb “as for me, when they were sick, my clothing was sackcloth.” Sackcloth was worn by mourners. When the psalmist’s enemies were sick, he was sorry for their misfortune and mourned for them.
24 Fasting was also a practice of mourners. By refraining from normal activities, such as eating food, the mourner demonstrated the sincerity of his sorrow.
25 Heb “and my prayer upon my chest will return.” One could translate, “but my prayer was returning upon my chest,” but the use of the imperfect verbal form sets this line apart from the preceding and following lines (vv. 13a, 14), which use the perfect to describe the psalmist’s past actions.
26 Heb “like a friend, like a brother to me I walked about.”
27 I bowed down. Bowing down was a posture for mourning. See Ps 38:6.
28 Heb “like mourning for a mother [in] sorrow I bowed down.”

In other versions

But I, when they were sick—

I wore sackcloth;

I afflicted myself with fasting;

I prayed with head bowed on my chest.

I went about as though I grieved for my friend or my brother;

as one who laments his mother,

I bowed down in mourning.

Yet when they were ill, I put on sackcloth

and humbled myself with fasting.

When my prayers returned to me unanswered,

I went about mourning

as though for my friend or brother.

I bowed my head in grief

as though weeping for my mother.

Yet when they were sick,

my clothing was sackcloth;

I humbled myself with fasting,

and my prayer was genuine.

I went about mourning as if for my friend or brother;

I was bowed down with grief,

like one mourning for a mother.

Yet when they were ill, I grieved for them.

I denied myself by fasting for them,

but my prayers returned unanswered.

I was sad, as though they were my friends or family,

as if I were grieving for my own mother.

But as for me, when they were sick, my clothing was sackcloth.

I weakened my soul with fasting,

and my prayer returned to me unanswered.

I behaved as though he were a friend or as a brother to me.

As one lamenting a mother, I was bowed down in mourning.

But as for me, when they were sick, my clothing was sackcloth:

I humbled my soul with fasting;

And my prayer returned into mine own bosom.

I behaved myself as though he had been my friend or brother:

I bowed down heavily, as one that mourneth for his mother.

Public Domain