Note the text on the banner. Its a pasuk from Yeshaya made popular by Avraham Fried's hit song, "Chazak." The literal translation: Every man would help his friend and tell his brother "be strong". Although this is the literal translation of the text, in context, it clearly refers to Jews helping their fellows worship idols; an odd choice of lyric for a Hassidic dance song. The Artscroll translation includes "worship idols" in brackets, since that's the clear implication.
An ironic choice of banner for a kiruv gathering, dontcha think? Unless missionaries to other faiths were also participating.
