Abdullah bin Ubayd bin Umayr (may Allah have mercy on him) said that the Prophet (peace and blessings be upon him) accepted the repentance of Nabhan four times, and Nabhan had apostatised. Ibrahim (may Allah have mercy on him) said: However many times an apostate returns, (his repentance) will be accepted.
This is munqati' (its chain is broken); it has also been narrated as connected (mawsul) through another route, but that is of no worth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المرتد / 16833