“I tell you this: let an intelligent person who is sincere, honest and straightforward come to me, and I will instruct him, I will teach him Dhamma. If he practises as he is taught, then in seven years he will attain in this very life by his own knowledge and vision that for the sake of which young men go forth from home into homelessness, and he will abide in it. Never mind seven years; he will be able to do it in seven days.
Now, you may think: “The recluse Gotama only says this in order to get disciples.” But this is not so; let he who is your teacher be your teacher still.
You may think: “He wants us to give up our commandments.” But this is not so; continue to live by your commandments.” Or you may think: “He wants us to give up our way of life.” But this is not so; continue to live your way of life. Or again you may think: “He wants us to practise things that are wrong or not practise things that are right, according to our teachings.” But this is not so; continue to avoid the things your teaching considers wrong, and practise the things that your teaching considers right.
But there are unskillful things not yet given up, things tainted, leading to rebirth, fearful, of painful result in the future, things associated with birth, decay and death. And it is for the giving up of these things that I teach Dhamma.
However, if you practise correctly, these tainted things will be given up, and the things that lead to the purification will grow and develop. In this very life you will attain the fullness of perfected wisdom by your own knowledge and vision, and abide in it.” – Digha Nikaya III.55