"Though the ba’al teshuvah may wish to see himself as one reborn and to begin his spiritual life with a sense of wholeness, it is important for him to recognize that even in spiritual rebirth it is not possible to take on everything at once.
The People of Israel, in accepting the Torah, did not receive it all at one time.
Rather, the process was a protracted once, from the early preparatory stage of the seven Noahide laws to the acceptance of additional mitzvot in Egypt, at Marah, and at Sinai, to the full revelation that that followed.
Similarly, a child raised to be an observant Jew takes upon itself the full yoke of the mitzvot only after long preparation: years of training and the gradual, step-by-step assumption of responsibility according to it s intellectual readiness and practical capacity.
The essential point is that living beings do not undergo sudden, complete transformations.
The caterpillar does not become a butterfly in a single act but as a result of a gradual process, governed by certain laws."
--Rabbi Adin Steinsaltz
From "All or Nothing: The False Dilemma" in Teshuvah by Rabbi Adin Steinsaltz
