Asalamu Alikum,
I have heard a Hadith few times and it is supposed to be in the Mosanad Imam Ahmad:
Allah (SWT) Says, the closing meaning, when my servant reaches the Age of 40 I will put a light in his scale, when my servant reaches the age of 60 I will make him close to me, when my servant reaches the age of 70 everything in heavens and earth love him when my servant reaches the age of 80 I will ears his sins with his good deeds and when my servant reaches the age of 90, 1st I will forgive his past and future 2nd I will give him the minor shafaha (intersession) 3rd he will be my prisoner in this world. Is this an authentic hadith?
Jazakum Allah Khairan

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

Perhaps you mean the Hadeeth which was narrated by Imaam Ahmad on the authority of Anas ibn Maalik that the Prophet, sallallaahu ‘alayhi wa sallam, said: “Any man who reaches forty years in Islam, Allaah protects him from three [things]: madness, leprosy and vitiligo. When he reaches fifty, Allaah makes his reckoning easy. When he reaches sixty, Allaah grants him repentance to Him as pleases Him. When he reaches seventy, Allaah loves him and the inhabitants of heavens love him. When he reaches eighty, Allaah accepts his good deeds and forgives his sins. When he reaches ninety, Allaah forgives his past and future sins, he is called the prisoner of Allaah on earth and he is allowed to intercede (for forgiveness) on behalf of his family.”

This Hadeeth was not authentically narrated from the Prophet, sallallaahu ‘alayhi wa sallam.

In “Al-Mawdhoo‘aat” (Fabricated Ahaadeeth), Ibn Al-Jawzi said that this Hadeeth was not authentically narrated from the Prophet, sallallaahu ‘alayhi wa sallam. Imaam Ash-Shawkaani mentioned it in his book “Al-Fawaa’id Al-Majmoo‘ah min Al-Ahaadeeth Al-Mawdhoo‘ah” (The Collected Benefits of the Fabricated Ahaadeeth), and Shaykh Al-Albaani classified it as Dha‘eef (weak) in “Dha‘eef Al-Jaami‘As-Sagheer”. Shu‘ayb Al-Arnaa’oot said, 'The chain of narrators of this Hadeeth is very weak, and even the other narrations that support it are of no significance.'