Job 9:21

[Though] I [were] perfect
Really and truly so, not conscious of any sin in thought, word, or deed; this is only a case supposed:

[yet] would I not know my soul;
I would not own myself to be so before God; I would not insist upon such perfection in his presence, as what would justify me before him; since I am sensible the highest perfection of a creature is imperfection when compared with him: or the sense may be, should I say I were "perfect, I should not know my own soul"; I should plainly appear to be ignorant of myself, as all perfectionists are; they do not know their own souls, the plague of their hearts, the evil of their thoughts, the vanity of their minds; they do not take notice of these things, or do not look upon them as sinful; they know not the nature of sin, and the exceeding sinfulness of it:

I would despise my life;
even if ever so innocent, perfect, and just; his meaning is, that he would not insist upon the continuance of it on that account; he had no such value for it, such a love of life as to contend with God upon the foot of justice about it; nor did he think it worth asking for, so mean an opinion had he entertained of it, see ( Job 7:16 ) .