Midrasch zu Tehillim 102:8

Rabbi Alexandri began: “I was diligent, but I became like a lonely bird on a rooftop” (Psalms 102:8) – the Holy One blessed be He said: I was diligent about bringing My children into the Land of Israel immediately, “but I became like a lonely bird on a rooftop.” Just as the bird moves alone from roof to roof, from fence to fence, from tree to tree, and from branch to branch, so too, when Israel departed from Egypt, they traveled in dispute and encamped in dispute: “They traveled…and they encamped [vayaḥanu]” (Exodus 13:20).⁵⁵The word vayaḥanu is plural, indicating that they were not united. When they arrived at Mount Sinai, they became a united entity. It is not written here, “they encamped,” but rather, “Israel encamped [vayiḥan] there” (Exodus 19:2).⁵⁶The word vayiḥan is in the singular, indicating unity. At that time the Holy One blessed be He said: This is the time when I will give the Torah to My children.
Another matter: “I was diligent [shakadti] but I became ” – the Holy One blessed be He said: I was persistent [shakadti] to rest My Divine Presence in the Temple forever. But I became like a bird. Just as this bird, when you take its fledglings it remains alone, so too, the Holy One blessed be He said: I burned My Temple, destroyed My city, exiled My children among the nations of the world, and I sat alone; “how…?” (Lamentations 1:1).