From Rabbi Rahmiel Hayyim Drizin,
We start with Pirke Avot 4:11:
רַבִּי אֱלִיעֶֽזֶר בֶּן יַעֲקֹב אוֹמֵר: הָעוֹשֶׂה מִצְוָה אַחַת, קֽוֹנֶה לּוֹ פְּרַקְלִיט אֶחָד, וְהָעוֹבֵר עֲבֵרָה אַחַת, קֽוֹנֶה לּוֹ קַטֵּגוֹר אֶחָד
Bartenura, simply states that a praklit means a, “malach melitz tov, a good interceding angel.” See also Rashi. Rav Zusha of Anipoli explains the Gemara in Chullin 7b that angel is created by each mitzvah and prayer. The action of the mitzvah and prayer creates the body of the angel, while the kavannah creates the angel’s soul. One who doesn’t want to do a mitzvah or pray creates the body of an angel which is lacking a soul since he didn’t wish to pray or do a mitzvah. Those who wish to do a mitzvah or pray but does not do so creates the soul of an angel which lacks a body….
Angels are not only summoned by our prayers, but actually born by them. Our sages taught that every human deed creates an angel. Good deeds create angels that advocate for us in heaven. Bad deeds create angels that prosecute us in heaven.The Baal Shem Tov taught that not only our deeds, but the words we speak also create angels. Our words of prayer not only summon angels; they create angels. Tzava’at HaRivash 17; Sefer Baal Shem Tov, Noach, Amud HaTefilah 18; Zohar Vol. I 23b., These angels are not only the carriers of our words; they are our words. See Zohar Chadash, Acharei 47a; Iyov 33:23
It follows that these angels reflect the nature of the words from which they are spawned. Angels born of exuberant and devoted prayer are vibrant and robust. Angels created by rote prayer are lackluster and lethargic. Tzava’at HaRivash 123; Maggid Devarav LeYaakov, sect. 58; The condition of these angels automatically broadcasts the nature of our prayers. If the angels are lackluster, the heavenly sphere knows that we prayed by rote. If they are robust, the heavens knows that we prayed with devotion. Biurim Lepirkei Avot p. 205 (Chabad)