The verse in Tehillim (115,7) which we say in Hallel says: “Their hands - but they do not feel, their feet - but they do not walk.” But in the previous two verses it says “they have a mouth…they have eyes…they have ears…they have a nose”, so here too it should have said "they have hands…they have feet". Why is there a change of expression here?
The sefer חנוכת התורה here answers that this difference can be explained according to the halachah that it is permissible to benefit from broken pieces of an idol, but if one finds a hand or a foot by itself it is forbidden, because such things are worshipped by themselves.
Thus with all the other parts of the body such as eyes and ears it says "they have" because they need to be connected to the idol, otherwise they would not be considered an idol. But with the hands and feet it does not say "they have", not only because it was not necessary since even by themselves they are an idol, but in addition by not adding this phrase it alludes to the halachah that even when they are separate they are considered an idol and are forbidden.