When I tied a pair of tzitzit, I tied a double knot to the garment and for the final knot, but for the three knots in between the chulyot (subsections of string wrappings), I tied single knots. Is that sufficient?
When after fastening the tefillin shel yad, I find part of my sleeve under the tefillin and pull it away, must I refasten the tefillin due to the rule of ta’aseh v’lo min ha’asuy (=tvlmh – mitzva-related actions must be performed directly)? In this case, the placement of the tefillin becomes proper not by fastening them but by removing something else!
Is a silk Talis Kosher? What is the basis of the halachic controversy whether one may have a talis koton made of rayon? I have a talis koton that says that it is made of a cotton-polyester blend. Do I recite a brocha when I put it on?