Midrash su Salmi 48:7

The G-d who conferred "hacheil" His name upon you — what He did with no other nation (— you forgot Him), viz. (Shemoth 20:2) "I am the L-rd, your G-d." R. Meir says: The G-d shechechil ("who suffered pangs [chil]") over you, as in (Psalms 48:7) "chil, as a woman in labor." And (Ibid. 29:3) "The voice of the L-rd is upon the water ... (Ibid. 9) The voice of the L-rd yecholel [lit., "brings pangs"] upon the hinds." R. Yehudah says: He made you mechilin, mechilin (i.e., with many natural openings).