הלכה על שבת 64:13

And know that even though this commandment is only obligated by the Torah when he has a four cornered garment (Mishneh Torah 3:18) - like there is no obligation for the commandment [to build a] parapet unless one has a roof - the Sages still warned much about this commandment and said (Menachot 41a) that it is fitting to pursue it. They also said (Shabbat 32b) that a person who is careful [in the fulfillment of this commandment] will merit to be waited upon by many servants, as the Torah equated it to and depended upon it the fulfillment of all the other commandments, as it is stated, "And you will see it and remember all the commandments of the Lord." And Rabbi Elazar said that one who is careful in this and tefillin and mezuzah is assured that he will never sin, as it is stated (Ecclesiastes 4:12), "The three fold thread will not easily break."