فَتَنَادَوۡا۟ مُصۡبِحِینَ
And they called one another at morning,
قَالُواْ سُبْحَـنَ رَبّنَآ إِنَّا كُنَّا ظَـلِمِينَ- فَأَقْبَلَ بَعْضُهُمْ عَلَى بَعْضٍ يَتَلَـوَمُونَ- قَالُواْ يوَيْلَنَآ إِنَّا كُنَّا طَـغِينَ- عَسَى رَبُّنَآ أَن يُبْدِلَنَا خَيْراً مّنْهَآ إِنَّآ إِلَى رَبّنَا رغِبُونَ- كَذَلِكَ الْعَذَابُ وَلَعَذَابُ الاْخِرَةِ أَكْبَرُ لَوْ كَانُواْ يَعْلَمُونَ-
فَتَنَادَوْا مُصْبِحِينَ (So, they called out each other as the morning broke 68:21). This means that they starting waking up each other in the early morning that they should set out early if they wanted to harvest.
وَهُمْ يَتَخَافَتُونَ (...while they were whispering to each other ... 68:23). They were speaking in a low voice, lest a poor man should hear their talk and accompany them.
Whatever a man earns in this world is apparently from farming or industry or other such pursuits. But, in fact, it is all given to him by the grace of God. If one considers it a gift from God and sets apart a portion of it for other subjects of God, Almighty God will bless his earnings. On the contrary, one who considers his earnings the result purely of his own talents and who is not, therefore, prepared to give others their dues, will find that his earnings will be of no avail. This is a strict law of God. In some cases, it manifests itself in this world, but in the Hereafter it will manifest itself for all, and none shall be exempt from it.