"The best gift to children from parents is their correct training." This hadith is from At-tirmthi. I want to know whether it is Saheeh (authentic), and I need the hadith number urgently.

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

This hadeeth was cited in Sunan At-Tirmithi, no. 1952.

As for its authenticity, it was classified as Dha‘eef (weak) by Al-Bukhaari, At-Tirmithi, and Ath-Thahabi. Al-Albaani adopted the same view; he said in his book Silsilat Al-Ahaadeeth Adh-Dhaʻeefah wa Al-Mawdhooʻah wa Atharaha As-Sayyi' fil-Ummah, 3/249:

"There is no better gift that a parent gives to their child than good manners.' It is Dha‘eef. It was cited by Al-Bukhaari in At-Taareekh (1/1/422), At-Tirmithi in Sunan At-Tirmithi (1/354), Al-Haakim (4/263), ʻAbd ibn Humayd in Al-Muntakhab min Al-Musnad (1/46), Al-ʻUqayli in Adh-Dhuʻafaa’ (p. 315), Ibn Adh-Dharees in Ahaadeeth Muslim ibn Ibraaheem Al-Faraaheedi (1/6), Al-Qudhaaʻi in Musnad Ash-Shihaab (2/105), Al-Khateeb in Al-Muwadhdhah (2/166), and Ibn ʻAsaakir in Taareekh Dimashq (2/226/13 and 2/198/17). All were narrated on the authority of ʻAamir ibn Abi ʻAamir Al-Khazzaaz, from Ayyoob ibn Moosa, from his father, from his grandfather, that the Prophet, sallallaahu ‘alayhi wa sallam, said the hadeeth in reference. At-Tirmithi classified it as weak and commented, 'It is a Ghareeb hadeeth (a hadeeth or version reported by one reliable or unreliable narrator which differs in context with another hadeeth or version reported by a group of reliable narrators) unknown to us except through ʻAamir ibn Abi ʻAamir Al-Khazzaaz, who is ʻAamir ibn Saalih Rustum Al-Khazzaaz, and Ayyoob ibn Moosa, who is Ibn ʻAmr ibn Saʻeed ibn Al-ʻAasi. I have classified it as a Mursal hadeeth (hadeeth with a broken link in its chain of narration at the level of a Companion. A Taabi’e reported it directly from the Prophet ).'

Al-Bukhaari commented on the hadeeth, saying, 'It is a Mursal hadeeth; it is not authentically established that his grandfather heard it from the Prophet, sallallaahu ‘alayhi wa sallam.' Al-Haakim said, 'Saheeh Al-Isnaad (its chain of narration is Saheeh).' Ath-Thahabi answered to him, saying, 'Rather, it is Mursal Dha‘eef; its chain of narration includes ʻAamir ibn Saalih Al-Khazzaaz, who was classified as a weak reporter.'"

Allah knows best.