In the Jewish tradition, tachanun are prayers of penitence, regularly recited between the Shemoneh Esreh and the Ashrei portions of the service. Tachanun are generally not recited on Shabbat or other holidays. In Talmudic times, these confessional prayers were often uttered while laying face-down in the synagogue, with increased fervency during the month of Elul in preparation for the high holiday of Yom Kippur.
When we call upon the L-rd in deep humility, conscious of our unworthiness before Him, yet hopeful of His gracious and compassionate love (especially in light of the sacrifice of Yeshua given on our behalf), we can know that G-d Himself meets with us by hearing our voice...
Then we, too, will be filled with profound gratitude to the L-RD for graciously answering the cry of our hearts, spontaneously exclaiming "Blessed be the L-rd, for He has heard the voice of my supplications!"