( أَوَلَمْ يَنظُرُوا فِي مَلَكُوتِ السَّمَاوَاتِ وَالْأَرْضِ ) (Do they not look into the realm of the heavens and the earth): This is a calling to seek knowledge, to think of what beyond the surface of things. The word (realm) refers to the hidden dimension.

 وَكَذَٰلِكَ نُرِي إِبْرَاهِيمَ مَلَكُوتَ السَّمَاوَاتِ وَالْأَرْضِ

(And thus did We show Abraham the realm of the heavens and the earth) (Al-An’aam: 75)

Knowing what is beyond visible matters refers to (realm).

(Do they not look): It means that they should look, contemplate, think, engage their intellect, and pursue knowledge in the realm of heavens and earth, not just what is visible. Humanity has now engaged into exploring space, stars, galaxies, and various cosmic sciences, employing intellect in the realms of the heavens, the earth, and the unseen.

( وَمَا خَلَقَ اللَّهُ مِن شَيْءٍ ) (and everything that Allah has created): All of Allah’s (swt) creations, even the atoms and grains of sand in the sea, requires us to engage our intellect, contemplate, and reflect upon it, in order to derive what Allah (swt) is conveying to us.

( وَأَنْ عَسَىٰ أَن يَكُونَ قَدِ اقْتَرَبَ أَجَلُهُمْ ) (and [think] that perhaps their appointed time has come near?): Meaning when their time comes. People think that they still have a lot of time left, like when Allah (swt) says:

 (6) إِنَّهُمْ يَرَوْنَهُ بَعِيدًا (7) وَنَرَاهُ قَرِيبًا

(( 6 ) Indeed, they see it [as] distant ( 7 ) But We see it [as] near.) (Al-Ma’aarij)

Indeed, no matter how long a person may live, even if someone lived to be seventy, eighty, or even ninety, eventually, everyone’s time will come without a doubt.

( فَبِأَيِّ حَدِيثٍ بَعْدَهُ يُؤْمِنُونَ ) (So in what statement hereafter will they believe?): When their appointed time comes, there is no meaning for declaring faith, as the truth at that time becomes evident, and the person emerges from the darkness in which he was living in the worldly life. He will see the truth after death:

  لَّقَدْ كُنتَ فِي غَفْلَةٍ مِّنْ هَٰذَا فَكَشَفْنَا عَنكَ غِطَاءَكَ فَبَصَرُكَ الْيَوْمَ حَدِيدٌ

([It will be said], “You were certainly in unmindfulness of this, and We have removed from you your cover, so your sight, this Day, is sharp.”) (Qaaf: 22)

In this worldly life, humans do not see the Kingdom and the Realm, but they will see the Realm after the cover is lifted, and they will witness these truths. Not everything unseen by our eyes is nonexistent; we must perceive with our hearts and insight, not just with our eyes. This is why Allah (swt) says:

 لَهُمْ قُلُوبٌ لَّا يَفْقَهُونَ بِهَا

(They have hearts with which they do not understand) (Al-A’raaf: 179)

If they comprehend with their hearts, they would see the truth, recognize that this world is a temporary enjoyment, acknowledge its transience, realize that death is inevitable, and that there is life after death. All of Allah’s (swt) creatures are evidences of His (swt) existence:

 إِنَّ فِي خَلْقِ السَّمَاوَاتِ وَالْأَرْضِ وَاخْتِلَافِ اللَّيْلِ وَالنَّهَارِ وَالْفُلْكِ الَّتِي تَجْرِي فِي الْبَحْرِ بِمَا يَنفَعُ النَّاسَ وَمَا أَنزَلَ اللَّهُ مِنَ السَّمَاءِ مِن مَّاءٍ فَأَحْيَا بِهِ الْأَرْضَ بَعْدَ مَوْتِهَا وَبَثَّ فِيهَا مِن كُلِّ دَابَّةٍ وَتَصْرِيفِ الرِّيَاحِ وَالسَّحَابِ الْمُسَخَّرِ بَيْنَ السَّمَاءِ وَالْأَرْضِ لَآيَاتٍ لِّقَوْمٍ يَعْقِلُونَ

(Indeed, in the creation of the heavens and earth, and the alternation of the night and the day, and the [great] ships which sail through the sea with that which benefits people, and what Allah has sent down from the heavens of rain, giving life thereby to the earth after its lifelessness and dispersing therein every [kind of] moving creature, and [His] directing of the winds and the clouds controlled between the heaven and the earth are signs for a people who use reason.) (Al-Baqara: 7)