In Rav Shach's Avi Ezri Laws of Tzitzit chapter 1, law 15 is brought this fact that if one has a garment with four corners and puts in the four blue threads but then adds another then the previous four are also nullified. That is when the Torah gives a commandment that has a certain amount and one adds to that amount then the entire fulfillment of that command is nullified.
[This would tend to show that religious fanaticism does not help in terms of keeping Torah. ]
There are on the other hand certain commandments that have no upper or lower limit as is brought in the mishna in Peah אלו דברים שאין להם שיעור הפאה והביכורים וגמילות חסדים וכו' ותלמוד תורה כנגד בולם
These things have no given amount peah, the first fruits, kindness, honor of parents, visiting the sick etc., and learning Torah is equal to all of them together.
That is you can add as much to learning Torah or doing kindness and that is not a sin because the commandment has not given amount. But other commandments that have an amount, if one adds extra, he or she loses the fulfillment.
See Rav Shach there that there is an argument how to explain the Gemara in Menakot [page 40 side b and also page 41 side a] that is the source of this whole issue. But to all the different opinions, putting on another thread makes the whole fulfillment null and void.
The issue there in Menakot is "to make" not make from "what is already made", and the gemara asks on this from R. Zeira. Then Rava makes an statement that seems hard to understand and that is the source of the difficulty.
These things have no given amount peah, the first fruits, kindness, honor of parents, visiting the sick etc., and learning Torah is equal to all of them together.
That is you can add as much to learning Torah or doing kindness and that is not a sin because the commandment has not given amount. But other commandments that have an amount, if one adds extra, he or she loses the fulfillment.
See Rav Shach there that there is an argument how to explain the Gemara in Menakot [page 40 side b and also page 41 side a] that is the source of this whole issue. But to all the different opinions, putting on another thread makes the whole fulfillment null and void.
The issue there in Menakot is "to make" not make from "what is already made", and the gemara asks on this from R. Zeira. Then Rava makes an statement that seems hard to understand and that is the source of the difficulty.
