“and it is Him whom you shall serve” (Devarim 10,20)
It is a positive commandment to serve Hashem, may He be blessed, as it says “and it is Him whom you shall serve, and the Rambam writes, even though this commandment of “serving Hashem” is one of the general commandments, that is to say, it includes the entire Torah, for service of Hashem includes all the commandments, it also contains a specific detail which is that Hashem has commanded us to pray to Him, and as Chazal have said about the verse “and to serve Him with all your hearts”, what is service of the heart? It is prayer.”
Amongst the roots of this commandment, is that which I have introduced a number of times, that the good and blessings will rest on people in accordance with their deeds, the good of their hearts and the power of their thoughts, and the Master of Everything who created them wants their good and leads them and makes them successful with his prescious commandments through which they can merit and he has also informed them and opened for them an opening through which they can reach all the good that they yearn for and that opening is – that they should request from Him, may He be blessed, who has the ability to fill their lack for He will answer from Heaven to anyone who calls Him in truth. He has commanded them to use this opening and they should always request all their needs and the desires of their hearts from Him. Apart from the realization of our hearts desires, we have a merit in the fact that we rouse our spirits and through that we fix our thoughts on the fact that He is the good Master and does good to us and that His eyes are open to all of our ways and at every time and every minute He will hear our pleas to Him, the Guardian of Israel neither sleeps nor slumbers and He has made us believe in His Kingship and His abilities without any kind of doubt and that there is nothing before Him that can prevent or delay what He wants.
On the topic of the commandment, is that which they have warned us about the intense concentration of the heart in prayer, and specifically in the first blessing of the “Shmoneh Esrei” and the point of this concentration which they have put so much stress on, is so that a person should enter into his heart, that he is praying before Hashem; it is to Him that he is calling, and he should turn his thoughts away from all other worldly thoughts and focus them on this.
This commandment applies in every place, at every time, to men and to women and if a person passes twenty four hours without any kind of prayer he transgresses this positive commandment. One who is in difficulty and does not cry out to Hashem to save him has transgressed this commandment and his punishment is exceedingly great for he is as though removing the guidance of Hashem from upon him.