“On my bed at night…” (Song of Songs 3:1) at the moment when Avraham bound Yitzchak his son on top of the altar. “I held him and would not let him go…” (Song of Songs 3:4) This refers to David. When he took the threshing floor from Aravnah the Jebusite he found the skull of Aravnah placed under the altar but Gd (HaMakom) did not disqualify the offerings of Israel.
Another explanation. “I held him and would not let him go…” R’ Yitzchak said: until the Tabernacle was erected prophecy was found among the idol worshipers. Once the Tabernacle was erected it was removed from them, as it says “I held him and would not let him go…” and it is written “Then I and Your people will be distinguished…” (Exodus 33:16) They said to him: but Balaam had prophecy? He replied: Not for his benefit! “Who counted the dust of Jacob…” (Bamidbar 23:10) “He does not look at evil in Jacob…” (Bamidbar 23:21) “How goodly are your tents, O Jacob…” (Bamidbar 25:4) “A star has gone forth from Jacob…” (Bamidbar 24:17) “A ruler shall come out of Jacob…” (Bamidbar 24:19) Another explanation. “On my bed at night…” (Song of Songs 3:1) Because I rested from Torah and commandments, night was joined to night for me. In the past it illuminated for me between night and night, between the night of Egypt and the night of Bavel, but now night is joined to night.