"By benevolence man rises to a height where he meets God. Therefore do a good deed before you begin your prayers." ~~ Ahai Gaon, Sheiltot
"Who cries over the past is offering a vain prayer." ~~ Berakhot 9:3
"Prayer without intention is like a body without a soul." ~~ Yeshu’ot Meshicho
"O Music! miraculous art! A blast of thy trumpet, and millions rush forward to die; a peal of thy organ, and uncounted nations sink down to pray." ~~ Benjamin Disraeli
"Man can never be happy if he does not nourish his soul as he does his body." ~~ Rebbe Manachen Schneerson
"None should stand up to pray save in sober mood; the pious men of old used to wait an hour before they said their prayer, that they might direct their heart toward God." ~~ Berakhot 5:1
"One should not pray in levity and jest, but in gravity and the joy of doing good." ~~ Talmud, Berakhot
"In Ne”ilah [the closing prayer] of Yom Kippur, what did he [the Cohen] say? “And Hashem will bless you from Zion and you will see the good of Jerusalem all of the days of your life.” " ~~ Talmud, Sotah 40a
"Prayer is greater than sacrifices." ~~ Talmud, Berakhot
"The prayers of the sick are more effective than the prayers of others, and are answered first." ~~ Rashi
"Look upon the rainbow and bless its Maker!" ~~ Ben Sira 43:11
"The gates of prayer are sometimes closed, but the gates of repentance are forever open." ~~ Midrash Deuteronomy R. 2:7