Shavuot

is the second pilgrimage festival. It comes after Pesah and is followed by Sukkot ( cf Ex 23,14-17; Dt 16, 1-17)
Those pilger festivals have in common several characteristics, mainly:
Going up to Jerusalem, to  the Temple
Celebrating at the same time an agricultural event and an historical moment of the History of Salvation.
Expressing the joy of both events in singing the Hallel psalms ( 113-118)

Those festivals were first cananean festivals, adopted by Israel and referred  to the One God Then, becoming pilgrimage festivals as soon as there has been a Temple: And In a third stage  related to an  evnt of the History of Salvation.

Shavuot comes 7 weeks after Pesah,( cf Dt 16,9; Lev 23,15-16) even 5o- days, as a fulfillment of Pesah.
The gift of the Tora is seen by Jewish tradition as and an inner deepening of the freedom given by the Lord in the Exodus from Egypt.
Let my people go, so they can serve me ( cf Ex 4,23; 5,1,3; 7,16,26; 8,16,23; 9,13; 10,3)  The service is the service of God through the observance of the Tora.

It is only during the first centuries that the agricultural feast of Shavuot  was associated to the gift of the Tora, but unofficially, it seems that the relation was already known much sooner ( cf manuscripts of Qumran, the book of Jubilees, Acts 2). And  Ex 19 situates the gift of the Tora,  in the third month after the exodus from Egypt which corresponds to the 7 weeks after Pesah.

Sr. Anne Catherine Avril nds