Suuratul – Luqmaan Verse 30.
ذَٰلِكَ بِأَنَّ ٱللَّـهَ هُوَ ٱلْحَقُّ وَأَنَّ مَا يَدْعُونَ مِن دُونِهِ ٱلْبَـٰطِلُ وَأَنَّ ٱللَّـهَ هُوَ ٱلْعَلِىُّ ٱلْكَبِيرُ ﴿٣٠
30. That is because Allah, He is the Truth, and that which they invoke besides Him is Al-Batil (falsehood and all other false deities), and that Allah, He is the Most High, the Most Great.
Tafsir Ibn Kathir Volume 7, Page 594.
He shows you His Signs so that you may know from them that He is the Truth, i.e. He truly exists and is truly divine, and that all else besides Him is falsehood. He has no need of anything else, but everything else is dependent on Him, because everything in heaven and on earth is created by Him and is enslaved by Him; none of them could move even an atom’s weight except with His permission. If all the people of heaven and earth were to come together to create a fly, they would not be able to do so. Allah says:
﴿ذَلِكَ بِأَنَّ اللَّهَ هُوَ الْحَقُّ وَأَنَّ مَا يَدْعُونَ مِن دُونِهِ الْبَـطِلُ وَأَنَّ اللَّهَ هُوَ الْعَلِىُّ الْكَبِيرُ ﴾
That is because Allah, He is the Truth, and that which they invoke besides Him is falsehood; and that Allah, He is the Most High, the Most Great.
meaning, He is the Most High and there is none higher than Him, and He is the Most Great Who is greater than everything. Everything is subjugated and insignificant in comparison to Him.
Suuratut- Tawbah Verse 119.
ـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ ٱتَّقُوا۟ ٱللَّـهَ وَكُونُوا۟ مَعَ ٱلصَّـٰدِقِينَ ﴿١١٩
119. O you who believe! Have Taqwa of Allaah, and be with those who are true (in words and deeds).
Tafsir Ibn Kathir Vol. 4, Page 539.
﴿يَـأَيُّهَا الَّذِينَ ءَامَنُواْ اتَّقُواْ اللَّهَ وَكُونُواْ مَعَ الصَّـدِقِينَ ﴾
(O you who believe! Have Taqwa of Allaah, and be with those who are true) The Ayah says, adhere to and always say the truth so that you become among its people and be saved from destruction. Allaah will make a way for you out of your concerns and a refuge. Imam Ahmad recorded that `Abdullah bin Mas`ud said that the Messenger of Allaah said,
«عَلَيْكُمْ بِالصِّدْقِ فَإِن الصَّدْقَ يَهْدِي إِلَى الْبِرِّ، وَإِنَّ الْبِرَّ يَهْدِي إِلَى الْجَنَّةِ، وَلَا يَزَالُ الرَّجُلُ يَصْدُقُ وَيَتَحَرَّى الصِّدْقَ حَتَّى يُكْتَبَ عِنْدَ اللهِ صِدِّيقًا، وَإِيَّاكُمْ وَالْكَذِبَ فَإِنَّ الْكَذِبَ يَهْدِي إِلَى الْفُجُورِ وَإِنَّ الْفُجُورَ يَهْدِي إِلَى النَّارِ، وَلَا يَزَالُ الرَّجُلُ يَكْذِبُ وَيَتَحَرَّى الْكَذِبَ حَتَّى يُكْتَبَ عِنْدَ اللهِ كَذَّابًا»
(Hold on to truth, for being truthful leads to righteousness, and righteousness leads to Paradise. Verily, a man will keep saying the truth and striving for truth, until he is written before Allaah as very truthful (Siddiq). Beware of lying, for lying leads to sin, and sin leads to the Fire. Verily, the man will keep lying and striving for falsehood until he is written before Allaah as a great liar.) This Hadith is recorded in the Two Sahihs.