The Messenger of Allah ﷺ used to say in his tahajjud prayer(i.e. supererogatory prayer offered in or after the midnight) after he said the takbir; he then narrated the tradition to the same effect.
أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ فِي التَّهَجُّدِ يَقُولُ بَعْدَ مَا يَقُولُ اللَّهُ أَكْبَرُ ثُمَّ ذَكَرَ مَعْنَاهُ