Sing a Song?
When the exiled Jews finally rested by the rivers of Babylon they hung their lyres on the willows growing there. The psalm (137) in Tehillim recounting their dramatic scene goes on to relate that There our captors requested words of song from us with our lyres playing joyous music: Sing for us from Zions song.
How can we sign the songs of G-d upon the aliens soil? was the response of the Levites who had taken with them the instruments which they had used for providing musical accompaniment.
Our Sages point out that they did not say We shall not sing but How can we sing? To avoid playing sacred music on their lyres for their heathen captors on foreign soil, they had cut off their thumbs in order to make it impossible for them to play those instruments.
These courageous Levites were the ones who eventually accompanied Ezra on the return to Eretz Yisrael despite the difficulties involved while those who had not removed their thumbs remained behind to enjoy the comfort and security of Babylon.