My soul, i.e. either,
1. Myself, to wit, my body. So it is a double synecdoche. And the soul is so taken Psalms 16:10. Or,
2. My soul properly so called; which is said to be healed, when it is pardoned and purged, as 2 Chronicles 30:20 Isaiah 53:5, compared with 1 Peter 2:24 Matthew 13:15, compared with Mark 4:12 James 5:16. So he strikes at the root of his misery, and prays for the removal of the sin of his soul, as the cause of the disease of his body. For I have sinned against thee: this may be added, either,
1. As a reason or motive to God; Grant this request, for I have sinned, and therefore thy grace in healing me will be more glorious and admirable. Or, for I acknowledge that I have sinned; for the act is oft put for the declaration of it, as Exodus 33:13 Psalms 51:5. Or,
2. As a reason moving him thus to pray, I said, Lord, be merciful unto me: heal my soul; and great reason I had to say so, for I have sinned against thee.