I don't want to imply that we are living under a law whereby we have to tippy-toe around for fear that we will say the wrong thing and mess up the entire universe, because that would be a curse in itself. We are under the grace of God for all we say and do (thank the Lord). But just look at the blessings that were spoken, without any awareness of the weight of the words or the specific events that would follow. Boaz speaks kindly, or pronounces a blessing so to speak, on Ruth when he says:
" . . . The Lord repay you for what you have done, and a full reward be given you by the Lord, the God of Israel, under whose wings you have come to take refuge!" (Ruth 2:12)
In turn, Naomi speaks kindly (a blessing) about Boaz:
Naomi said to her daughter-in-law, "May he be blessed by the Lord, whose kindness has not forsaken the living or the dead!" (Ruth 2:20)
Did blessings materialize for Boaz and for Ruth? I am sitting here, living proof, that the blessing was fruitful! Ruth and Boaz married, and the son they bore was one of the forefathers of our Lord Jesus. The result of those blessings spoken so long ago is still being multiplied today in every heart that is touched by the Spirit of God. How could these people thousands of years ago have imagined that the very savior of the world would be among their descendants? And yet it is recorded clearly in the lineage of Christ:
. . . Salmon the father of Boaz, whose mother was Rahab, Boaz the father of Obed, whose mother was Ruth, Obed the father of Jesse . . . (Matthew 1:5)
What comes out of your mouth makes a difference! Do not indulge in cursing (as I am often wont to do), even in your most private moments, when you think it is just between you and the mirror. It is not! Every word that comes out of your mouth - no! out of your heart before it is formed into spoken syllables - has the power to bless or to curse. Blessing from God are a direct result of the power of the spoken word, so weigh your words carefully, and aim to speak blessings today, even (and especially) in your mind and in front of the mirror!
See also Matthew 18:18-20, Romans 12:14.