congregations. assemblies.
from. Supply the Ellipsis, "[Ye that are] from, or of, the fountain of Israel".
fountain: i.e. the patriarch Abraham, or, Israel. Ginsburg suggests "the called of Israel".
Related Commentaries of Psalms 68:26
Psalms 68:26
26 Bless ye God in the congregations, even the Lord, from the fountain of Israel.