Those deluded by the gunas of nature remain attached to the actions of the gunas. One who knows the whole should not unsettle those slow-witted people who know only a part.
Explanation
Krishna continues advising Arjuna. People confused by the qualities of nature (guṇa, the three strands of nature that drive all activity) become attached (saṅga) to the actions those strands produce, believing themselves to be the doers. Someone who sees the whole picture should not shake their confidence in acting, since that could leave them with neither knowledge nor the steadiness that comes from doing their duty.