Don't make the same mistake twice!
In the time of our beloved Nabi ﷺ there was a poet by the name Abu Uzzah Al-Jumahi.
During the Battle of Badr, he fought against the Muslims and was taken as a prisoner. He appealed to our beloved Nabi ﷺ to release him without ransom because he was poor and had a family to support.
Our beloved Nabi ﷺ out of his kindness granted him his request and freed him.
This man again fought against the Muslims in the battle of Uhud. He was again captured and like the first time he appealed to our beloved Nabi ﷺ by making mention of his family and poverty.
In reply, our beloved Nabi ﷺ spoke the words of this hadeeth ‘A believer does not get stung from the same hole twice!’
(Al-Maghazi of Ibn Ishaq)
This story is a perfect example of how a believer is careful and alert. Out of kindness and goodwill, a believer may be fooled/tricked once but he will adopt more caution the second time.