Is it permissible to use a rosary (sibha)?

There is no harm in using a rosary (misbaha), but it is better to count tasbeeh with the fingers. Abu Dawud and Al-Tirmidhi reported from Aisha bint Sa'd ibn Abi Waqqas, from her father, that the Prophet, peace and blessings be upon him, entered upon a woman who had date pits or pebbles with which she was counting tasbeeh. He said: "Shall I not inform you of what is easier for you than this – or better?" Then he guided her to tasbeeh with specific words, but he did not forbid her from counting tasbeeh with what she was using. Sheikh al-Islam Ibn Taymiyyah said: Counting tasbeeh with the fingers is a Sunnah. As for counting it with pebbles and the like, it is good. And as for tasbeeh with what is made into a string of beads and the like, if one's intention is good, then it is good and not disliked. But if it is taken for no need, or to show off to people, then it is either forbidden showing-off (riya') or disliked if it is a cause for showing-off.