Through the prophet Malachi, God reminded Israel that He knew what they had been saying! How sobering it must have been as God reminded them that they said to Him: “How have we despised Thy name?” (1:6); also, “You say, ‘The table of the Lord is defiled, and as for its fruit, its food is to be despised...My, how tiresome it is!’” (1:12f).
When God promised judgment on the sorcerers, adulterers, those who swear falsely, and those who oppress (3:5), calling on them to repent and return to Him, He reminded them that they said, “How shall we return?”-as if they had no reason to return! (3:7). When God reminded them that they had been arrogant against Him (3:13), He stated, “Yet, you say, What have we spoken against Thee.. It is vain to serve God: and what profit is it that we have kept His charge, and that we have walked in mourning before the Lord of hosts?” (3:13f). Some of these statements surely had not been stated directly to God. As He told them what they had been saying (to each other about Him??), they knew He knew!

God even knows what we say in our hearts! Zephaniah 1:12 refers to those “who say in their hearts: The Lord will not do good or evil.” Jesus reminded some that He knew what they were reasoning in their hearts (Lk. 5:22). Deuteronomy 15:9 warns us that what we say in our hearts could be sin! Isaiah 14:4-22 is a solemn warning of the downfall of Babylon because of what the King said in his heart (cf.vv.13f). Isaiah 47:8-11 warns one of how the loss of children and widowhood will come because of what one said in the heart! It was what Jeroboam said in his heart that caused God to say, “Now this thing became a sin” (1 Kings 12:26-33).
Since God does search our hearts (Jer. 16:10) and keeps record of all that we say (Matt. 12:36f), what have YOU been saying lately? Have your statements been related to envy or edifying (Matt. 27:18; 1 Thess. 5:11)? Have your words been evil or good (Psa.52:3; 35:12; Prov. 15:3; 12:25)? Have your words encouraged or discouraged others (Acts 4:36 NAS; 11Chron. 35:1f;Num. 32:7,9; Col. 3:21)? Whatever influence your works have rendered, be sure that God knows!

From a positive standpoint, be reminded that by speaking the Truth in love, you and others around you can “grow up in all aspects into Him, who is the head, even Christ” (Eph. 4:15). What a precious promise is in Psalm 37:30f: “The mouth of the righteous utters wisdom, and his tongue speaks justice. The Law of the God is in his heart; his steps do not slip.” “How beautiful are the feet of them that bring glad tidings of good things” (Rom. 10:15)!
How have you been speaking? Regardless of your answer, the Psalmist gives us these facts: “Even before there is a word on my tongue: Behold, O Lord, You do know it all” (Psa. 139:4).