Through all the Bible--in the Old Testament, in the New Testament--we hear God's call to repentance. It was the chief appeal of the Old Testament prophets. And at the gate of the New Testament sounds John the Baptist's--the forerunner's--cry, "Repent ye for the kingdom of heaven is at hand." Then the Lord Jesus Himself began with the same call--"Repent ye for the kingdom of heaven is at hand," and He preached repentance with great urgency throughout the days of His ministry. When after His death on the cross the risen Lord gave the great commission to His disciples, it was that in repentance and remission of sins should be preached in His name to all the nations, beginning at Jerusalem. When the Holy Spirit had come, and the apostle Peter (to whom it pertained) preached the opening sermon of the new dispensation (Acts 2) the convicted hearers cried out, "Men and brethren, what shall we do?" And Peter, by the Holy Spirit, answered, "Repent and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Spirit." (Acts 2:38.) In his next recorded sermon Peter said, again, "Repent ye therefore and turn again, that your sins may be blotted out."  (Acts 3:19) Paul also, the great apostle to the Gentiles, after he had been called, "declared to them at Damascus first, and at Jerusalem, and throughout all the country of Judaea, and also to the Gentiles, that they should repent and turn to God, doing works worthy of repentance." (Acts 26:20.) To the idolaters of Athens he declared that God now "commandeth men that they should all everywhere repent" (Acts 17:30.) And down to the last book, the Revelation, we hear God's gracious call to repentance. It is clear from all the stress placed upon it in the word of God that this is a matter of first importance. It is indeed so important that without it there can be no salvation. God would have to change--He would have to cease being the God He is--before He could save an unrepentant sinner.
The Lord Jesus laid down three outstanding "excepts": "Except ye believe that I am He, ye shall die in your sins"; and "Except one be born anew he cannot see the kingdom of God"; and "Except ye repent ye shall all in like manner perish." These are things that cannot be waived: they are essentials to salvation. The only alternative to repentance is perdition: "Except ye repent ye shall . . . perish." "The Lord is not slack concerning his promise, as some count slackness; but is longsuffering to youward, not wishing that any should perish, but that all should come to repentance." (II Pet. 3:9.) But it is the  one or the other.
The necessity then of a real and sincere turning from sin unto God (for that is what repentance means) is so plain that it needs not to be argued. Yet, if one knew how many people are trying to get by without repentance--at least without a real repentance--he would probably be astonished. In the old days of the prophets, when God called to repentance, how He had to exhort them to make it genuine and real! "Yet even now," He says in Joel--even while judgment was already under way--"even now turn ye unto me with all your heart . . . and rend your heart and not your garments, and turn unto Jehovah your God, for He is gracious and merciful, slow to anger, and abundant in lovingkindness." (Joel 2:12, 13.) Ah, how much easier it is for some to rend their garments than their hearts! There was a great revival in Judah in king Josiah's time, and it looked as if the nation had repented; but here is God's disappointment: "Judah hath not returned to me with her whole heart but feignedly, saith Jehovah." (Jeremiah 3:10.) It was not real--it was a make-believe; just as much religion and repentance is today--for as your repentance is, so is your religion. There was plenty of outward demonstration but, as He complained in Hosea, "They have not cried to me with their heart, but they howl upon their beds." (Hosea 7:14.) Their pretended goodness was "as a morning-cloud that goeth early  away." Israel made many pious prayers, but "they flattered Him with their mouth, and lied unto Him with their tongue; for their heart was not right with Him, neither were they faithful in His covenant." (Psalm 78:36, 37.) Why anyone should undertake to fool God is a mystery--for does not He know the heart and search the mind; and can there be anything hid from Him? Are not all things naked and laid open before the eyes of Him with whom we have to do? And He looks for sincerity and uprightness as of a precious jewel. Oh, why should not a man get right with God, when God opens the way for him to do so?
There are many who will half-way repent. They come across--almost, not wholly. Something rouses them out of their sinful slumber--they are troubled--they feel the pangs of conscience and become alarmed--they make good resolutions; then relapse into their old ways. Now repentance, to be worth anything, must be real. God's call is to "break up your fallow ground, sow not among thorns." Your salvation is at stake in this matter. When you really turn, when you really come, your God stands ready to receive you. Yea, He will see you when you are yet a great way off, and run to meet you.
The marks of a true repentance are simple and unmistakable. 1. As, to purpose of heart--there is a clean returning from sin and idols unto God; without if or but,  without compromise or mental reservation. There may or may not be a show of tears or sorrow for "godly sorrow worketh repentance not to be repented of"; but the essence of true repentance lies in the turning. All the sorrow in the world is worthless if it does not lead to turning; and if a man turns he need not worry about the sorrow.
2. Repentance is always humble; so much so that the two things (repentance and humbling) are spoken of interchangeably. "Seest thou how Ahab humbleth himself before me; I will not bring the evil upon him in his days." It is pride that prevents men from acknowledging their sins, and from turning openly and wholeheartedly to God. And pride and repentance cannot be in the same heart. But a broken and a contrite heart the Lord will not despise.
3. A truly repenting man never makes excuses or tries to justify himself. If there are mitigating circumstances God will plead them for you. But your confession must be excuseless. In the parable of the Prodigal Son we have a wonderful picture of simple and genuine repentance. When the Prodigal in the far country "came to himself" he said, "How many hired servants of my father have bread enough and to spare, and I perish here with hunger: I will arise and go to my father, and will say unto him, Father, I have sinned against heaven and in thy sight; I am no more  worthy to be called thy son: make me as one of thy hired servants." And thus, with that honest and excuseless confession upon his lips he came to his father. Imagine what it would have been if he had said, "Father, you know how young folks are--you were young yourself once; and like most young fellows I was rash and foolish, but I didn't mean any harm," etc. That would have been the best proof of a false and insincere repentance. But he came not so. He told the simple truth (and God is ever looking for truth in the inward parts) and stated the case as it was. And there was a welcome for him, and the best robe, and a joyful feast in the father's home--for "there is joy in heaven among the angels of God over one sinner that repenteth."
4. True repentance will make full restoration, where restoration can be made. "Lord, half of my goods I give to the poor," said Zaccheus the publican, overcome by Christ's loving condescension toward him--"and if I have wrongfully exacted aught of any man I restore fourfold." Instantly the Lord Jesus acknowledged the man's action and attitude, and said, "Today is salvation come to this house, forasmuch as he also is a son of Abraham. For the Son of man came to seek and to save that which is lost." (Luke 19:9, 10.) There are, alas, many sins and wrongs for which no reparation can be made. But where it is possible true repentance will always make it. If  you have slandered your fellow-man, fear not to correct the false statement you have made about him, lest you should be looked on as a liar in the sight of men. It is better to save your soul than to save your face. If you have stolen or defrauded, return what you have wrongfully taken; and don't stand back on what people will think. There are far worse things than man's reproach. And those who have done so will tell you how greatly it pays in joy and inward peace and deep satisfaction.
5. True repentance, moreover, is always unto God. Paul preached "repentance toward God and faith toward our Lord Jesus Christ." Since all sin is sin against God, repentance must be toward God. It will not do to say, "I am going to turn over a new leaf--I will quit my evil habits, and be a better man," as often we hear people say. That is not repentance. If the Prodigal Son in the far country had said--"I see I have made a mess of things; I will now try to retrieve myself, and go here or there or yonder, and start life over again"--that would not have been a picture of repentance. Some of the proudest self-will and fiercest rebellion against God wears the guise of moral reform. But it was from his father that he had departed; against his father's love he had sinned; back to his father he must go with humble confession. Says the prophet of God, "Seek ye Jehovah while he may be found; call ye upon him while he is near; let the  wicked forsake his way and the unrighteous man his thoughts; and let him return unto Jehovah, and he will have mercy upon him; and to our God, for he will abundantly pardon." (Isaiah 55:6, 7.) It is not only that to God you must return, but with Him only can you find mercy, forgiveness, help, sustenance, and the enabling to a new and worthy life.
6. Finally, in connection with that first great sermon which was preached "by the Holy Spirit sent down from heaven" on the day of Pentecost, Peter said, "Repent ye and be baptized every one of you in the name of Jesus Christ unto the remission of your sins; and ye shall receive the gift of the Holy Spirit." Baptism, therefore is the God-appointed expression of the sinner's repentance, as also of his faith. "And they that received his word were baptized, and there were added unto them the same day about 3000 souls." But if already you have been baptized and have fallen into sinful ways, repent and return to your Father in heaven who alone can and will forgive and restore to you the peace which you have lost.