"The law of the Lord is perfect,   converting the soul. the testimony of the Lord is sure, making wise the simple"   (Psalm 19:7).
                                 Recently I listened to the   testimony of a Jew who claimed to be a "Messianic believer." He began by saying,   "I have not been converted - I have been completed." He went on to say that it   was not necessary for Jews to be converted, as conversion implies a changing of   one's religion. A careful study of the biblical teaching of conversion will show   the folly of such a statement and reveal the lack of biblical understanding on   the part of those that hold this unscriptural view.
                                 Peter's second sermon is   recorded in Acts 3:12-26 and presented to the "men of Israel." In it the apostle   urges his people to repent ... and be converted, that your sins be blotted out."   Peter does not admonish them to change their religion but rather to change their   minds about Christ, repent of their sins, and turn to the Lord. This is biblical   conversion. 
                                 The apostle John records a   number of the miracles performed by our Lord prior to His death and   resurrection. In John 12:37-41 he says, speaking of the Jews:
                                But though   he had done so many miracles before them, yet they believed not on him:
                                  That   the saying of Esaias the prophet might be fulfilled, which he spake, Lord, who   hath believed our report? and to whom hath the arm of the Lord been revealed? 
                                  Therefore they could not believe, because that Esaias said again,
                                  He hath   blinded their eyes, and hardened their heart; that they should not see with   their eyes, nor understand with their heart, and be converted, and I should heal   them.
                                  These things said Esaias, when he saw his glory, and spake of him. (Quoted from Isaiah 53:1; 1:6)
                                 These verses make it clear   that the eyes of His people were blind and their hearts hard, and that their   need was conversion, not completion. We are complete in Christ, but the way in   begins with conversion.
                                 I realize that many Jews   think of conversion as changing one's religion, and this is repugnant to them.   This does not give us the freedom to water down the doctrine of conversion,   which is fundamental to the Christian faith. We have the responsibility to   explain this biblical teaching to the Jew in order that he may understand what   God says about his soul's need. He needs to know that the need of his soul is   not found in a change of religion but in a change of heart. David said, "The law   of the Lord is perfect, converting the soul. the testimony of the Lord is pure,   making wise the simple" (Psalm 19:7).
                                 The disciples were   concerned as to "Who is the greatest in the kingdom of heaven? Jesus called a   little child unto him, and set him in the midst of them, And said, Verily I say   unto you, Except ye be converted, and become as little children, ye shall not   enter into the kingdom of heaven" (Matt. 18:1-3). The words of the Lord Jesus   are just as true today as they were 2,000 years ago when He spoke them to His   Jewish "brethren according to the flesh." The needs of the Jew are the same   today and "Except ye be converted ... ye shall not enter into the kingdom of   heaven." When he turns from his sin to the Savior, he is converted; and then,   and then only, is he complete in Him."
                                 In this day of confusion   and compromise, may we that claim His name be faithful to His Word. We do not   need to resort to the practice of denying, changing, or watering down biblical   teachings to make the gospel more palatable to either Jew or Gentile. To do so   is to "err from the truth." The apostle Paul refers to himself as an "able   minister of the New Testament" (II Cor. 3:6). As an able minister he states,   concerning Israel, "Seeing then that we have such hope, we use great   plainness of speech. And not as Moses, which put a vail over his face, that the   children of Israel could not stedfastly look to the end of that which is   abolished: But their minds were blinded: for until this day remaineth the same   vail untaken away in the reading of the old testament; which vail is done away   in Christ. But even unto this day, when Moses is read, the vail is upon their   heart. Nevertheless when it shall turn to the Lord, the vail shall be taken   away" (II Cor. 3:12-16). This is biblical conversion, and it is the work of the   Holy Spirit. May we not be found guilty of hindering Him in His   work.