«وَقَدْ بَلَوْتُ الْإِخْوَانَ وَسَبَرْتُ الْأَوْزَانَ»
Having tested companions and examined weights or measures of worth.
Balawtu means to test by experience; sabartu indicates probing or examining thoroughly. Here awzān evokes the assessment of people's worth or standing, not simply metrical patterns in poetry.
The narrator has learned about people as well as language: he weighs relationships and the value of what others have to offer.