A Holiday of Nature in Israel
The 15th of Av was, according to the Mishnah, a popular holiday of nature during the Second Temple era.
"Never were more joyous festivals in Israel than the 15th of Ab and the day of atonement, for on them the maidens of Jerusalem used to go out dressed in white garments—borrowed ones, in order not to cause shame to those who had none of their own... and thus they went out and danced in the vineyards” (Mishnah Ta’anit 4:8).
The young men would go there too and choose themselves a spouse. Tu B’Av is special in matters of nature and the things that occurred on it.
a. Tu B’Av is considered the day on which the sun reaches the peak of its strength. From then until Tu B’Shvat its strength diminishes, and along with it the trees become weakened as well. Therefore, on Tu B’Av they stopped cutting down trees for the arrangement of wood that burned on the altar, and this day was called “the day of the breaking of the scythe” (of the axe).
This day was the last opportunity to bring these trees to the Temple, and despite the fact that is was the turn of the sons of Zattu, this right was given to the entire people and many took advantage of it; hence, this day was also called “the tree sacrifice festival” (Book of Ta’anit 5).
b. This is the day on which the grape harvest starts; hence, it is celebrated in the vineyards.
c. “The day on which the deaths of the Jews in the wilderness ceased” (Yerushalmi Ta’anit 4); in other words, the forty year sentence on the Israelites who left Egypt was over (Numbers 14:27-35)
d. The day on which the tribes were permitted to intermarry, and did not fear as previously that the inheritance would pass from tribe to tribe.
e. The day on which the tribe of Benjamin was allowed to intermarry with the other tribes, after having been excommunicated in wake of the Battle of Gibeah (Judges 21:15-24).
f. The day on which the slain of Betar were buried, after the Romans forbade burial of the Bar Kochba Soldiers who fell in defense of Betar, their last fortress (135 AD). The “Ha-tov veha-meitiv [Who is good and beneficent]" blessing was instituted in memory of this event.
“The good” – that there was not stench; “the beneficient” – that they were brought for burial (Berachot 48b).
In the lands of exile Tu B’Av lost its character as a holiday of nature; however, its memory as a holiday has been preserved as historically determined. On this day there is no fasting, no eulogizing and no supplicatory prayers are said.