Bikkurim, Chapter 3, Mishnah 4. The Mishnah continues its description of how those bringing the first fruits arrive in Jerusalem and at the Beis HaMikdash, and it lays out the stages of the journey from the entrance to the city until they stand in the Azarah.
"HeChalil makkeh lifneihem ad shemagi'im l'Har HaBayis":
The flute, the instrument that accompanied the procession, keeps on sounding and playing before them the entire way, until they reach the Har HaBayis (the Temple Mount).
"Afilu Agrippas hamelech notel hasal al keseifo":
Once they reached the Har HaBayis, even Agrippas the king - one of the kings in the days of the Second Beis HaMikdash, a person of high standing who held himself in great esteem - would take the basket and place it on his own shoulder, in order to display the greatness of the mitzvah. Up until this point he was not required to carry the basket himself, but from here onward every person carries it on his shoulder.
"V'nichnas ad shemagia la'azarah":
With the basket on his shoulder he enters and continues inward, until he reaches the Azarah itself - the courtyard of the Beis HaMikdash.
"Higia la'azarah v'dibru haLevi'im bashir":
The moment they reached the Azarah, the Levi'im would break into song and say: "Aromimcha Hashem ki dilisani v'lo simachta oyvai li" - a verse in Tehillim, from the psalm "Mizmor shir chanukas habayis l'David":
"Ki dilisani" - because You raised me up.
"V'lo simachta oyvai li" - and You did not let my enemies rejoice over me.
In summary: In this Mishnah we learned the stages of the journey: the flute accompanies those bringing the first fruits until the Har HaBayis; from there onward every person takes the basket on his own shoulder, even Agrippas the king, to display the greatness of the mitzvah; and when they reach the Azarah the Levi'im begin the song "Aromimcha Hashem ki dilisani v'lo simachta oyvai li".