The Family of Imran
قَدْ خَلَتْ مِن قَبْلِكُمْ سُنَنٌ فَسِيرُوا۟ فِى ٱلْأَرْضِ فَٱنظُرُوا۟ كَيْفَ كَانَ عَـٰقِبَةُ ٱلْمُكَذِّبِينَ
Similar situations [as yours] have passed on before you, so proceed throughout the earth and observe how was the end of those who denied.
Nearby ayahs help place verse 3:137 in sequence and meaning.
وَٱلَّذِينَ إِذَا فَعَلُوا۟ فَـٰحِشَةً أَوْ ظَلَمُوٓا۟ أَنفُسَهُمْ ذَكَرُوا۟ ٱللَّهَ فَٱسْتَغْفَرُوا۟ لِذُنُوبِهِمْ وَمَن يَغْفِرُ ٱلذُّنُوبَ إِلَّا ٱللَّهُ وَلَمْ يُصِرُّوا۟ عَلَىٰ مَا فَعَلُوا۟ وَهُمْ يَعْلَمُونَ
And those who, when they commit an immorality or wrong themselves [by transgression], remember Allah and seek forgiveness for their sins - and who can forgive sins except Allah? - and [who] do not persist in what they have done while they know.
أُو۟لَـٰٓئِكَ جَزَآؤُهُم مَّغْفِرَةٌ مِّن رَّبِّهِمْ وَجَنَّـٰتٌ تَجْرِى مِن تَحْتِهَا ٱلْأَنْهَـٰرُ خَـٰلِدِينَ فِيهَا ۚ وَنِعْمَ أَجْرُ ٱلْعَـٰمِلِينَ
Those - their reward is forgiveness from their Lord and gardens beneath which rivers flow [in Paradise], wherein they will abide eternally; and excellent is the reward of the [righteous] workers.
هَـٰذَا بَيَانٌ لِّلنَّاسِ وَهُدًى وَمَوْعِظَةٌ لِّلْمُتَّقِينَ
This [Qur'an] is a clear statement to [all] the people and a guidance and instruction for those conscious of Allah.
وَلَا تَهِنُوا۟ وَلَا تَحْزَنُوا۟ وَأَنتُمُ ٱلْأَعْلَوْنَ إِن كُنتُم مُّؤْمِنِينَ
So do not weaken and do not grieve, and you will be superior if you are [true] believers.