It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever frees his share of a slave, he will be made responsible for freeing the remaining share as well. If he does not possess enough wealth to free the rest, then only the portion he has freed will remain freed."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5474
Hadith Gradingحکم دارالسلام:إسناده صحيح ، خ : 2503، م :1501.