"who would not build the house of his brother" — who would not build and who is not destined to build (i.e., Once he did not build it, he may build it no more.) (Ibid. 25:10) "And his name shall be called in Israel 'the house (of him) chalutz hana'al' ('whose shoe was removed')":
"in Israel": Why is this written here? Is it not already written elsewhere? (Ibid. 7) — That excludes converts (from yibum), this excludes a beth-din of converts (from officiating at chalitzah.)
"the house chalutz hana'al": It is a mitzvah for the judges (to say this), and not for the disciples. R. Yehudah says: It is a mitzvah for all those standing there to say "chalutz hana'al, chalutz hana'al." R. Yehudah said: Once we were sitting before R. Tarfon (at a chalitzah) and he said to us: All of your answer "chalutz hana'al, chalutz hana'al."