(Al-Hajj) 22 : 6
ذَٰلِكَ بِأَنَّ اللَّهَ هُوَ الْحَقُّ وَأَنَّهُ يُحْيِي الْمَوْتَىٰ وَأَنَّهُ عَلَىٰ كُلِّ شَيْءٍ قَدِيرٌ
That is because Lord Allah is the Truth, He gives life to the dead, and He is Capable of everything.
Adhikr is the Speech and Knowledge of the Three-Time-Knower Lord, the preservation of which is undertaken by Him as explained in verse 15: 9. See explanation 10: 108; 21: 24 and 112.