Because repentance (Hebrew teshuvah) is a great theme of the Old Testament, it is also a great theme of Judaism.
It is a theme found throughout the New Testament as well. In fact, it has been said that “‘repent’ is the first word of the Gospel” (see, for example, Matthew 4:17; 11:20–21; Mark 6:12; Luke 5:32; 13:3, 5; 15:7, 10; 16:30; 24:47; Acts 2:38; 3:19; 11:18; 17:30; 26:20; Romans 2:4; 2 Corinthians 7:9–10; 2 Peter 3:9; Revelation 3:19).
This teaching is also found in Jewish tradition:
“Rabbi Eliezer taught, ‘Repent one day before your death.’
His disciples asked him, ‘But does a man know on what day he will die?’
‘That is exactly the point!’ he replied. ‘Let a man repent today lest he die tomorrow, and in this way he will live all his days in repentance.’”
We do well to take this to heart...