When the Lord looks at us, he is looking at two things for sure, your mouth and your heart. You can tell a lot about what’s in a person’s heart by the words which come from their mouth. Have you ever been in a conversation with someone who said something wrong or evil and then they try to cover it up by saying “I didn’t mean to say that”? Well the truth is they did mean to say it because whatever is in your heart will eventually come out of your mouth, because out of the abundance of the heart the mouth speaks (Matt 12:34). With that said, King David prayed a prayer to God which said “Let the words of my mouth, and the meditation of my heart be acceptable in thy sight, O Lord my strength and my redeemer” (Psalm 19:14).
Thus, if the words of your mouth and the meditations of your heart are acceptable in God’s sight, then whatever comes from your mouth will be holy; and when it’s not holy the Holy Spirit will reveal it to you immediately. Therefore, it behooves us to guard our heart with everything in us and fill it with the word of God; because if not it will take authority over your mouth, and once words are spoken you can never get them back no matter how much you apologize. In fact, let’s not only ask God to fill our heart’s but let’s also ask him to fill our mouth’s with what He desires to hear from them. He told Israel in (Psalm 81:10) “I am the Lord thy God, which brought thee out of the land of Egypt: open thy mouth wide and I will fill it.”