Midrash su Salmi 10:17

And Abraham was old, well stricken in age (Gen. 24:1). May it please our master to teach us: What should a man do if he is riding upon an ass when the time for prayer arrives? Thus do our masters teach us: If one is riding upon an ass when the time for prayer arrives, he should dismount. However, if he is unable to dismount because of his concern for the merchandise loaded upon the ass, or because he fears that there may be non-Jews or bandits roaming about in the vicinity, he should pray while mounted. R. Yohanan declared: This statement indicates that a man’s mind must be completely at ease while praying to God. Abba Saul maintained: If a man directs his thought in his prayers, he can be confident that they will be heard, as it is said: Thou wilt direct their heart, Thou wilt cause Thine ear to attend (Ps. 10:17).

1. "And I besought the Lord" (Deuteronomy 3:23). Halacha: A Jew who stands and prays [the Amidah prayer], may he pray out loud? The sages teach: (Talmud Berachot 31a) "Someone who stands and prays [the Amidah prayer] should hear his own voice [but others should not]. Chanah already explained: (I Samuel 1:13) "And Chanah spoke to herself..." One might think one can pray the three [Amidah prayers throughout the day] as a single [prayer]? Daniel already taught: (Daniel 6:11) "And three times a day he would kneel on his knees, and he would pray and bow before his God." One might think that one should pray at every moment one fancies? David already explained: (Psalms 55:18) "Evening, morning and afternoon I speak and moan, and He hearkened to my voice."

R. Meir declared that the Holy One, blessed be He, said: The lamps that Aaron lights are more precious to Me than the luminaries that I placed in heaven. Why was he permitted to perform that act? At the time the heads of the tribes brought the dedicatory offering to the altar, the tribe of Levi was not called upon to bring a sacrifice and Aaron was deeply distressed. He said: All the chiefs of the tribes brought a dedicatory offering, but I have had no share in the sacrifices. The Holy One, blessed be He, said to him: Be assured, all the other tribes will bring only one offering, but you alone will perform the dedication before the veil, which is without the curtain of testimony in the Tent of Meeting, for Aaron and his sons shall set it in order (Exod. 27:21). Scripture states in reference to the above verse: Lord, Thou hast heard the desire of the humble (Ps. 10:17). Therefore, though the Holy One, blessed be He, said to Moses: Thou shalt command, it is written later that Aaron and his sons shall set it in order. The Holy One, blessed be He, said to Moses: Command the children of Israel to bring the oil so that Aaron may light it before Me.