It was the worship of Abraham (PBUH):

O my Lord! make me one who establishes regular Prayer, and also (raise such) among my offspring O our Lord! and accept Thou my Prayer. (Quran 14:40)

"O our Lord! cover (us) with Thy Forgiveness - me, my parents, and (all) Believers, on the Day that the Reckoning will be established! (Quran 14:41)

Having prayed for his progeny, Abraham now prays for Allah's grace on himself, his parents, and the whole Brotherhood of Faith, irrespective of family or race or time, to be perfected in the ideal of Islam.

The parents. Abraham's father was an idolater (43:26; 6:74). Not only that, but he persecuted the Faith of Unity and threatened Abraham with stoning and exile (19:46); and he and his people cast him into the Fire to be burned (21:52, 68). Yet Abraham's heart was tender, and he prayed for forgiveness for his father because of a promise which he had made (9:114), though he renounced the land of his fathers (Chaldea).

In our earthly life we collect several things in vain. Finally, there are only three imperishable issues what remain behind when we are in the graves. Therefore, the tree issues are considered as lampions what give light for our souls in the empire of darkness. These are: charity, knowledge and memory of our descendants about us what they express in their worships for us. These three issues have two directions. If I give them, I can expect them. If I do charity, somebody may do good even with me. If I give knowledge, maybe I will be taught, too. If I remember my parents, even my children will do the same with me. The system works nicely if it is followed generally. You may have hope if you can give hope for others.

Regarding charity and knowledge, I shall write in a separate chapter later. Here I share my thoughts on the offspring and people whom we leave behind.

Abraham prays for the generations descending from him. These generations gave prophets for the world. At the same time, he asks forgiveness for his parents and believers on the Day when Reckoning will be established. Who are these believers? Are they Jews or Christians? But at the age of Abraham Jews and Christians didn’t exist! So, his worship is for believers in God in general. This is Islam! According to our faith Abraham embodied the Straight Faith what he called Islam. And we say these verses five times a day in our prayer and we are not aware of we are saying!

The worship is for children of Abraham, too. They were those who propagated faith on the basement what Abraham established. If this text represents fix part in our prayers, even our children will pray like that, so even they will offer worship for us. They will not remember us case by case but five times a day! And if believers in the world establish prayer this way, they will all ask forgiveness for us as we did the same for them in the course of our lives. Does it worth to ask forgiveness only for the believers of one sect of a particular religion? It is a very bad business, isn’t it? When we die, we can rely only on their prayers for repentance! It is much better if we rely on the worship of all believers what they say for us. Therefore, don’t forget even one of them from your prayers! Here you are the lampion what gives light in the darkness while we are alone.