כִּֽי־אָ֭מַרְתִּי פֶּן־יִשְׂמְחוּ־לִ֑י בְּמ֥וֹט רַ֝גְלִ֗י עָלַ֥י הִגְדִּֽילוּ׃
因為我曾說：「恐怕他們會因我幸災樂禍；我一失腳，他們就向我妄自尊大。」
Rashi
For I said, “Lest they rejoice over me” For this reason we remain silent, because we say to ourselves, “If we answer them brazenly, they may witness our downfall and rejoice over us when our feet falter, and they will magnify themselves over us saying, ‘Weren’t you boasting of your salvation?’”