Simplicity to Friends has generally been a reference to material possessions. Friends have often limited their possessions to what they need to live their lives, rather than accumulating luxuries. The testimony is not just about the "nature" of one's material possessions, but rather also about one's attitude towards these material goods. Many Friends who have been considered exemplary have also been wealthy; their commitment to the testimony, however, led them to use their wealth for spiritual purposes, including aid to the poor and oppressed. On the other hand, some Friends, such as John Woolman, gave up much of their wealth and economic position when they felt it to be a spiritual burden.