I believe that if a man is Godly and genuinely righteous, his seven generations get mercy and blessings of God and are protected by Him.
Once Hazrat Musa (peace be upon him) was delivering a sermon, someone asked him whether there was anyone more knowledgeable than him. Hazrat Musa (as) replied, ‘I do not know.’ God did not like the response given by Musa. He should have said that there are many men of God, and every one of them excels in knowledge.
God ordered him to go towards a particular place where his fish will become alive and where he will meet a knowledgeable person. As he went to the place, he left his fish somewhere. He went back to get his fish but was unable to locate it. He stayed at that place. He came across a man of God. Musa (as) asked him, ‘Can I follow you to attain knowledge and wisdom?’
The pious man replied, ‘You are permitted to follow, but you will not be able to protect yourself from doubt. It is difficult to show patience when the reality of a situation is not known or understood. It is seen that doubt takes root on an unexpected action.’ Musa (peace be upon him) said, ‘I will not doubt and will trust you.’ The pious person advised him not to question him during the journey.
Both of them started their journey.
They saw a wall which was about to collapse. This wall belonged to two orphans, and a treasure was buried under the wall. It was feared that the with the collapse of the wall that treasure will be exposed and people will grab it, while the orphans who were still young would be left with nothing. Therefore, God appointed the two prophets to repair the wall.
They restored the wall so that orphans could use the treasure upon reaching adulthood. What was the reason for sending two great men of God? The reason for sending them was that the father of the orphan children was a pious person. The reward of the righteousness of a father was that two great prophets, Khidr (as) and Musa (as), were made labourer.
One can deduct from this as to what was the status of that person for whom prophets were sent to protect the treasure so that his offspring has access to the treasure when they grow up. It seems from the words of God that the two boys for whom Hazrat Khidr (as) inconvenienced himself were not going to be of a good character, but in the knowledge of God they probably were to go on the wrong path and were to develop bad habits. God, due to His attribute of covering faults of people, kept their character a secret and only manifested the piety of their father, and did not elaborate on their condition that in reality was not commendable and for the sake of a friend had mercy on the unfriendly.
Observe how God took care of the progeny of a pious man and observe how a person continues to fall but fails to care for the Almighty God. It is evident from this narrative that those who maintain relationships with God under all circumstances, the Almighty God saves them from going to waste.
(Malfuzat, Vol. 5, p. 245; see also Malfuzat, Vol. 3, p. 337; see also Malfuzat, Vol. 6, p. 68; see also Maktubat-e-Ahmad, Vol. 2, p.127, 2008 edition)1
1 There are slight differences in the narrations given in the references. These narrations have been consolidated in this version. [Publisher]