Who forgiveth all thine iniquities - Pardoning all thy sins. That is, It is a characteristic of God to pardon sin, and I have evidence that he has done it in my own case, and this is a ground for praise. It is observable that this is the first thing in view of the psalmist - the first of the “benefits” which he had received from God, or the first thing in importance among his acts or his dealings, which called for praise. Properly considered, this is the first thing which calls for praise. That God is a merciful God - that he has declared his willingness to pardon sin - that he has devised and revealed a way by which this can be done, and that he has actually done it in our own case, is the most important matter for which we should praise him. When we understand all the things which most affect our welfare, and which enter most deeply into our happiness here and hereafter, we shall find that this is a blessing compared with which all other favors are comparative trifles.
Who healeth all thy diseases - Perhaps, in the case of the psalmist, referring to some particular instance in which he had been recovered from dangerous sickness. The word rendered “diseases” - תחלואים tachălû'iym - occurs only in the plural form. It is translated “sicknesses,” in Deuteronomy 29:22; “diseases,” as here, in 2 Chronicles 21:19; “them that are sick,” in Jeremiah 14:18; and “grievous (deaths)” in Jeremiah 16:4. It does not elsewhere occur. It is applicable to all forms of sickness; or in this place it may refer to some particular diseases with which David had been afflicted. We have several allusions in the Psalms to times when the authors of the psalms were afflicted with sickness. So in the Psalms of David. Compare Psalms 6:2; Psalms 38:7; Psalms 41:8. The thought here is, that it is a proper ground of praise to God that he has the power of healing disease. All instances of restoration to health are illustrations of this, for whatever may be the skill of physicians, or the wise adaptation of means, healing virtue comes from God alone.