Conversion and Peace
Conversion is usually, if not always, sudden, though the manifestation of it may not be. The entrance of the soul into enjoyed peace may be lone, delayed and may demand the removal of many hindrances. This is rarely done in a very short time; but it is wholly distinct from conversion, and the two things should not be confounded as they too often are.
Conversion is the soul's turning to God through a believing reception of the Lord Jesus; the enjoyment of peace depends on the soul's submission to the righteousness of God when the redemption work of the Lord Jesus is seen by faith. Hence there are many souls who are truly converted because they have bowed to Jesus, who nevertheless are often cast down and unhappy and burdened, because they do not equally see peace made by the blood of His Cross. Where there is the simple reception of the Gospel the converted soul passes so soon into peace that one can well understand how the two things get confounded in the minds of many; as many others, on the contrary, confound them, because, unconsciously slighting conversion, which frequently plunges the soul in deep exercise and trouble of conscience before God, they only take into account that complete relief and peace which the Gospel ministers.
From: An Exposition of the Gospel of Luke by W. Kelly, (ch.23)