When the news of martyrdom of Imam Hussain (as) reached Medina Abdullah ibne Umar (la) was annoyed and he started to go to Damascus in order to curse and punish Yazid (la).
Since the time he left Medina for Damascus ( at every stop ) he declared the disbelief and deviation of Yazid (la) and discouraged the people from his love and allegiance. People also accepted his words as they recognized him as the son of the caliph . Till he reached Damascus and their evil eyes met ( Yazid and Abdullah ibne Umar (laa)). Abdullah ibn Umar (la) praised after praising Imam Hussain (as) started to rebuke Yazid (la).
The evil Yazid (la) took him away in loneliness and asked him: “ Do you recognize the writing of your father Umar (la) whose father was unknown ?
Abdullah ibn Umar (la) said : yes
Yazid (la) ordered to get a suitcase from which he took out a letter written on a cloth of silk and handed it over to him. It was written in it “This is a covenant written from Umar ibn khattab (la) to Muawiyah ibn Yazid (la) : O Muawiyah . know that , Mohammed (sawa) had come and he forbade the worship of Lat , Uzza and Habal and He (sawa) was dominant by his magic upon Musa and Isa and the Bani Israel , but I am as I was before and I did not leave the worship of Lat , Uzza and Habal . Since Mohammed (sawa) left from amongst us, I have raised 40 people who (will give false witness) deny that Mohammed (sawa) said that ‘the Imams are from Quraysh ‘.
In this way I have demolished the caliphate of Ali (as) and turned the people towards the allegiance of Abu bakr (la). Apparently I acted upon his (sawa) sunnat but inwardly I was the same like I was at the time of Jahiliyyah (before the advent of Holy Prophet sawa). And I oppressed the children of Mohammed (sawa) as much as I could and will continue doing it till I am alive, And to you O Muawiyah (la) I advise “as much as possible do not have any mercy upon them and do not be satisfied unless you kill them and if you can destroy the family of Mohammed (sawa) so that they don’t exist among us. Apparently do not oppose His (sawa) religion so that His (sawa) nation (followers) may attack you but inwardly as much as it is possible for you destroy the religion ……….”
Abdulah ibn Umar (la) became silent and said “My father did not share these secrets with me to this extent and if I knew it I would not have opposed and cursed you. Please forgive me (he asked for a lot of forgiveness from Yazid la).
Yazid (la) gifted him lots of things and he returned to Medina with them and after that whenever he sat in any gathering he said “Yazid did not say anything except the truth and did not act but justly, I would like to be along with him and in his actions .”
Behar ul Anwar V 30 page 287
(May allah curse him and his father till the day of Qiyamat )