Alacrity applies to the performance of a positive commandment, and it means being concerned that one may miss the opportunity to fulfill it. Because of this concern, the person does the mitzvah as soon and as quickly as he can, for one never knows when his time will come to leave this world. Also, every moment there are numerous obstacles that get in the way of the person and the Evil Inclination employs many enticements to distract the person from fulfilling a mitzvah. But a person who loves mitzvos as they should be — more than treasures full of gold and silver and more than anything in the world — his heart will be enflamed and he will not rest until he completes it. The Torah therefore says, “A mitzvah that comes your way, do not let it be lost” (מצוה הבאה לידך על תחמיצנה).
Included in alacrity is that when a person sets out on a journey, he should prepare for himself whatever items he will need to keep the mitzvos he might need to perform, such as a shofar and lulav, a Megillah and matzos, wine for Kiddush and havdalah, prayer books — and of course, one’s tallis and tefillin. Even if the person is going on a small trip and it is only a remote possibility that he will need a mitzvah object, he should take it with him. Many times it has happened that the person with alacrity gained but the person who was not, lost out.
Another aspect of alacrity is to walk quickly when going to do a mitzvah. This will discussed later, under the entry of ריצה / “Running.”