Truthfulness is approached here from several angles: the Quran and the Messenger ﷺ confirm what came before them, and none is truer in speech than Allah. The verses mention prophets of perfect truthfulness, genuine truthfulness made of faith and deeds, the reward of the people of truth, the command to be with the truthful, and Mary, daughter of ʿImran, described as truthful.
Verses gathered from a topical index of the Quran, in Mushaf order; every verse is quoted in full.
Allāh will say, "This is the Day when the truthful will benefit from their truthfulness." For them are gardens [in Paradise] beneath which rivers flow, wherein they will abide forever, Allāh being pleased with them, and they with Him. That is the great attainment.
That Allāh may reward the truthful for their truth and punish the hypocrites if He wills or accept their repentance. Indeed, Allāh is ever Forgiving and Merciful.
Indeed, the Muslim men and Muslim women, the believing men and believing women, the obedient men and obedient women, the truthful men and truthful women, the patient men and patient women, the humble men and humble women, the charitable men and charitable women, the fasting men and fasting women, the men who guard their private parts and the women who do so, and the men who remember Allāh often and the women who do so - for them Allāh has prepared forgiveness and a great reward.