Backsliding is failure in testimony and practical Christian living, resulting in a believer walking in a way dishonoring to the Lord. For such, sad as it is to backslide, there is a road open to restoration by true repentance and confession. We read, "I will heal their backsliding, I will love them freely." (Hos. 14:44I will heal their backsliding, I will love them freely: for mine anger is turned away from him. (Hosea 14:4)).
The Apostle Peter was a backslider indeed when he denied his Lord with oaths and cursings. Yet we all know how tenderly the Lord sought his restoration.
Apostasy on the other hand is far more serious. For that there is no road to recovery and restoration. An apostate is doomed to be bound forever in his sin, both in this world and in the next.
The Greek word for "falling away" is apostasia, from which we get our English word, apostasy. The Hebrew believers were evidently in danger of going back to Judaism, so a plain warning was given as to what that step would involve. By such an act they would renounce Christ as Savior, the Holy Spirit as sent of the Father, the New Testament as setting forth Christian doctrines. In short to return to Judaism meant open apostasy, for which there could be no pardon. Here is the plain statement of Scripture:- " FOR IT IS IMPOSSIBLE for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, and have tasted the good word of God, and the powers of the world to come, IF THEY SHALL FALL AWAY, to renew them again unto repentance; SEEING THEY CRUCIFY TO THEMSELVES THE SON OF GOD AFRESH, and put Him to an open shame." (Heb. 6:4-64For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, 5And have tasted the good word of God, and the powers of the world to come, 6If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame. (Hebrews 6:4‑6)). But it may be asked, Surely this description must refer to true Christians. The answer is that all these things may be the experience of those, who have been affected only outwardly in their contact with Christian circles.
The impact of Christianity on Jewish and pagan peoples was very marked, as seen in the Acts of the Apostles. About 3,000 souls were converted to God on one day—the day of Pentecost (Acts 2:4141Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls. (Acts 2:41)). In those early days the number of the disciples multiplied in Jerusalem greatly, and a great number of the priests were obedient to the faith (Acts 6:77And the word of God increased; and the number of the disciples multiplied in Jerusalem greatly; and a great company of the priests were obedient to the faith. (Acts 6:7)). The sick were brought into the streets, perchance the shadow of the Apostle Peter might fall upon them for healing (Acts 5:1515Insomuch that they brought forth the sick into the streets, and laid them on beds and couches, that at the least the shadow of Peter passing by might overshadow some of them. (Acts 5:15)); whilst napkins taken from the body of the Apostle Paul sufficed to heal men and women of their diseases, and to the casting out of evil spirits in bodies so tormented (Acts 19:11,1211And God wrought special miracles by the hands of Paul: 12So that from his body were brought unto the sick handkerchiefs or aprons, and the diseases departed from them, and the evil spirits went out of them. (Acts 19:11‑12)). Such mighty evidences of the powers of the world to come must have greatly impressed many, leading them to consort with the Christians. They tasted the word of God, and of the powers of the world to come. They moved in a circle where the power of the Holy Ghost was felt. Such might well be characterized by the features described in Heb. 6:4-64For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, 5And have tasted the good word of God, and the powers of the world to come, 6If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame. (Hebrews 6:4‑6).
Take the record as to Simon Magus. When he witnessed the signs and miracles that Philip wrought in the name of the Lord in the city of Samaria he was impressed. Indeed he made so fair a profession of Christianity that he was baptized. When he saw how the Spirit of God came upon believers through the laying on of the apostles' hands he offered money, seeking this gift for himself, not for spiritual blessing, but that he should thereby make himself great and influential with supernatural power, no doubt for merely carnal gain. The Apostle Peter unmasked his false profession by telling him plainly that he was " in the gall of bitterness, and in the bond of iniquity " (Acts 8:2323For I perceive that thou art in the gall of bitterness, and in the bond of iniquity. (Acts 8:23)). He asked Peter to pray for him. But if Simon Magus had gone to the length of denouncing Christianity root and branch, that would have been apostasy, for which there would be no forgiveness. We do not read that he went as far as that. He was a very evil man. We know nothing of his after career.
But a worse day is coming for the world. Scripture prophesies that in the last days, after the church of God has been raptured to glory, and only the hollow shell of a Christless profession left, that Christendom will become utterly apostate. It needs but little to show that this apostasy is well on the way. Look at Modernism today. Every fundamental doctrine of Christianity is explained away, or denied point-blank. The inspiration of Scripture, miracles, the virgin birth of our Lord, the atoning character of His death, His bodily resurrection, are all more or less refused.
Look at Roman Catholicism, proclaiming the fundamental doctrines of Christianity, yet denying them in practice, withholding the Word of God from the laity, grasping for world dominion, its prelates living in luxury, and often in sin, as the page of history records. Surely it will take but few steps to complete full and open apostasy. Thank God, we are comforted by knowing this will not be reached as long as true believers are left on earth. We read, " Let no man deceive you by any means: for that day shall not come, except there come a falling away [Greek, apostasia] first, and that man of sin [the antichrist] be revealed, the son of perdition." (2 Thess. 2:33Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition; (2 Thessalonians 2:3)).