The word repent is used 46 times in the Bible. The Old Testament uses it 21 times and the New Testament claims the word 25 times. Each and every time this word is used its meaning is the exact same!
The word repent in the Webster dictionary states that it is to turn from sin and amend one’s life. The Bible’s definition is very similar.
In the Bible the word repent either means to change one’s mind or motives or to turn from sin and ask for forgiveness. Nearly every time (only thrice does it mean the former), when used in the New Testament, it refers to the latter. And in the Old Testament only five times does it refer to turning from sin.
Repenting (in the turning from sin meaning), in the Old Testament, was not unimportant but it was revolutionized when it reached the New Testament. In the Old Testament repenting was largely classified as being saved from God’s wrath of which He had told was coming if Israel did not turn from their sin.
So, in essence, repentance in the Old Testament was mainly directed at being saved from God’s wrath.
However, when we observe the prevalence of the latter form of repentance in the New Testament we see something entirely new to the mind of the first-century Jews. (All coming mentions of repent are from the meaning of turning from sin)
John the Baptist came and exclaimed, “repent!” Then Jesus Christ said it again. “Repent!” And when Jesus sent out His disciples He taught them to preach “that men should repent.” Then, when talking to the masses, told them that “except ye repent, ye shall all likewise perish.”
In the broad sense we find that the word repent in the Old and New Testament settle on the same ground; that all should turn from their sin and ask for forgiveness, not just to escape God’s wrath but to cleanse them of the old man and to put on Christ! This is why the preaching of repentance is so important when witnessing, just make sure the person you are witnessing to knows what repentance means!