The words point to the time of the love of the espousals of Jeremiah 2:2, interpreting the parable, when Israel had grown to the maturity of a nation's life, and gave promise, in spite of previous degradation, of capacities that would render it worthy of the love of the Divine Bridegroom.
I spread my skirt over thee. Garments were often used as coverlets, and the act described was therefore, as in Ruth 3:9, the received symbol of a completed marriage (comp. Deuteronomy 22:30; Deuteronomy 27:20).
The historical fact represented by the symbol here was probably the formal covenant between Jehovah and Israel (Exodus 24:6, Exodus 24:7). It was then that he became her God, and that she became his people.