Reference : Swamy RAmAnujA’s Sri BhAshyam (Chapters 3 and 4) by SrImathy SarOjA RamAnujam @ Sadagopan.org
As an explanation to the last sutra of the 4th chapter,
anAvrtthi sabdhAth anAvrtthin sabdhAthh-4- 4-22
it is mentioned that :-
To the question that if the power and glory of the released soul depends on the will of the supreme self will there be a possibility of return to the world by the soul thus released., the suthra answers that it is not so.
Further the author explains what Ramanujar adds in this context and ends up with what Ramanuja says as follows,
na cha ucchinnakarmabanDha sya asankuchithajnAnasy a parabrahmAnubhavaik a
svabhAvasya thadhEkapriyasya anavaDHik athisayAnandham brahma anubhavathah
anyApEksha athadharTHArambhAdh yasambhavAth punarAvrtthi shanka; na cha
parampurushah sathyasankalpah athyarTHa priyam jnAninam labDHvA kadhAchith
That is, for the released soul who has destroyed all his karma, his knowledge being expanded to its real form, his nature established in the experience of Brahman cannot have any possible desire and no work to be undertaken on that account. The Lord, who is of infallible will make his most dear devotee return to samsara again.
I have given both Sanskrit and English version to check up if there is any variation in the translation, as I do not know sanskrit. Both Sanskrit and English version are given as it is mentioned in the reference.