וְֽצַדִּיקִ֗ים יִשְׂמְח֣וּ יַֽ֭עַלְצוּ לִפְנֵ֥י אֱלֹהִ֗ים וְיָשִׂ֥ישׂוּ בְשִׂמְחָֽה׃
But let the righteous be glad, let them exult before God; Yea, let them rejoice with gladness.
Read kabbalistic (mystical) interpretation of Psalms 68:4: and classical mystical sources.