So the women sang as they danced, and said: “Saul has slain his thousands, And David his ten thousands.” (I Samuel 18:7 NKJV)
After the women sang Saul was very angry and frightened that he was going to lose the kingdom to David because they spoke highly of him.
Had they not sang in such way maybe David would still be able to keep serving Saul but as it is written : "So Saul eyed David from that day forward." (I Samuel 18:9 NKJV)
From that day David was persecuted and Saul tried to kill him at all costs.
In short, what I see is that we have to be careful with what we say, certainly they did not have the intention of causing problems to David but sometimes even though the intention is good, the words come out wrong and cause a lot of troubles.
— Eu afirmo a vocês que, no Dia do Juízo, cada pessoa vai prestar contas de toda palavra inútil que falou. Porque as suas palavras vão servir para julgar se você é inocente ou culpado. (Mateus 12:36-37 NTLH)
“Let me tell you something: Every one of these careless words is going to come back to haunt you. There will be a time of Reckoning. Words are powerful; take them seriously. Words can be your salvation. Words can also be your damnation.” (Matthew 12:34-37 MSG)