Not that we are sufficient of ourselves to think any thing as of ourselves; but our sufficiency is of God;
The Greek is, 'Not that we are (even yet, after so long experience as ministers) sufficient to think anything OF [af'] ourselves as (coming) FROM х ex (G1537)] ourselves; but our sufficiency is (derived) FROM God.' 'From' more definitely refers to the source out of which a thing comes; "of" is more general.
To think, х logizesthai (G3049)] - to 'reason out' or 'devise' by our reasonings. The "we" refers to ministers (2 Peter 1:21).
Any thing - even the least. We cannot expect too little from man, or too much from God.