In order to approach Christ and enter into union with Him by means of holy baptism, it is essential first of all to repent. And after holy baptism, we are given freedom either to stay in union with the Lord or to break this union by intercourse with sin. Not only that, but in our fallen nature holy baptism does not destroy our aptitude for producing evil mixed with good, so that our will and pleasure may be constantly tested, so that our choice of divine good and our preference of it to evil and our corrupted good may be free, proved positively by our submission to all the sorrows and sufferings of the way of the cross.
By holy baptism, original sin is expunged, as are also sins committed before baptism. It also eliminates the violent power sin has over us till our rebirth; it gives us the grace of the Holy Spirit by which we are united with God in Christ, and we receive power to subdue and conquer sin. For the simple reason that we are not delivered from the struggle with sin, we cannot be entirely free from sin during the whole of our earthly life, and even “a righteous man may fall seven times and rise again” by repentance, says scripture….
Repentance becomes his secure possession, his constant weapon, his invaluable treasure. By repentance, the righteous man maintains his fellowship with Christ. He is healed by repentance from the wounds caused by sin.
~Ignatius Brianchaninov
Prayerful Life 