Qiddushin 1:7

[The meaning is this:] ‘As to all the things about which I spoke to you in the Torah, keep [and do them all], for you do not know from which of them the springs of life will flow to you.’"

Said R. Abba bar Kahana, "The Scripture has compared the easiest of all the religious duties to the most difficult of them all."

It was taught: R Simeon b. Yohai says, "Just as the reward that is coming for doing the two of them is equivalent, so the punishment applying to not doing the two of them is the same: ‘The eye that mocks a father and scorns to obey a mother will be picked out by the ravens of the valley and eaten by the vultures’ (Prov. 30:17).