Proof (dokimēi). Tests as of metals as in 2Co 2:9.
Abundance (perisseia). Late word from perisseuō, to overflow.
Their deep poverty (hē kata bathous ptōcheia autōn). Ptōcheia is old word from ptōcheuō, to be a beggar, as of Jesus in 2Co 8:9 (from ptōchos, cowering in fear and poverty, as in Luk 14:13, but ennobled by Christ as in Mat 5:3; 2Co 8:9). Poverty down deep. Strabo (LX 419) has kata bathous, down to the bottom.
Liberality (haplotētos). From haplous, single, simple (Mat 6:22). “The passage from single-mindedness or simplicity to liberality is not quite obvious” (Plummer). Perhaps “heartiness” supplies the connecting link. See also 2Co 9:11-13.