Peter’s mouth glorified and acknowledged Jesus as God’s Anointed One, Messiah.
(Luke 9:20)

Eight days later, Peter’s mouth was in full gear and going strong, although he didn’t really know what he was saying.  (Luke 9:33)  What did Peter say?  As he saw Jesus (in His glory and majesty as the Son of God), as he saw and identified Moses and Elijah, he said:
(NASB) Luke 9:33 “Master, it is good for us to be here; let us make three tabernacles: one for You, and one for Moses, and one for Elijah”…

Peter…this man: who was so human, one time so ‘right on’ and then another time, so wrong!  (Can you identify with him?)
As Peter was talking, a cloud was forming on that mountain; a cloud which surrounded and enveloped the Lord Jesus, Moses, Elijah and those three disciples (Peter, John and James).
As Peter was continuing to talk and talk…the cloud increased in size and the three disciples became afraid.  Then a voice came from within that cloud.
(NASB) Luke 9:35 “…‘This is My Son, My Chosen One; listen to Him!’”

Now that was a real attention-getter!  Peter was silenced by the voice of God!
Notice: God did not tell Peter he didn’t know what he was saying and for goodness sake, be quiet!  You really do not know what you are saying, Peter!

How many times does your mouth say words which show your ignorance, your arrogance, your ineptitude?  What do you and I need to do?  Do what God told Peter to do:
“Listen” to Jesus, God’s Son, His Chosen One!

Perhaps your prayer could be similar to this one:
‘Oh Lord, guard my thoughts and my words from foolishness and falsities.  Help me not to be sanctimonious nor pious sounding as I quote Your words.  Help me to pray Your words in humility by yielding to You, Most Holy God of the Bible:
(NASB) Psalm 19:14 “Let the words of my mouth and the meditation of my heart
Be acceptable in Your sight,
O LORD, my rock and my Redeemer.”’
In my Redeemer Jesus’ Name I pray, Amen.’