Why do the Malikites pray with their arms to the side?
The prayer has two parts as far as its postures are concerned; one is the obligatory part and the other optional. Whether hands should be tied in front or kept by the sides is a question which belongs to the optional part of the prayer.
In my opinion, as long as a person is standing before the Lord, it does not matter if he holds his hands or not; this is a non-issue and should not be made a point of dissension as is unfortunately done in many Muslim countries these days.