To understand this scripture, one must let other scriptures be compared with it. This is a basic rule of interpreting any scripture. Use various translations for greater understanding.
Many today are claiming to have the "Baptism of the Holy Spirit" and as a result of it, they claim they can perform the "signs" (1. power to cast out devils, 2. speak in tongues, 3. handle snakes, 4. drink poison, 5. heal the sick) found in Mark 16:17,l8.
Let us understand, not what some present day preacher says about Holy Spirit Baptism, but what the Bible says. First of all, we must realize that the promise of the Holy Spirit Baptism was given to the apostles only, and not the one hundred and twenty, or to others. If one follows the pronouns of Acts 1:2-5, it is clear that "them and "they" of verse 4 are the "apostles" of verse 2. They were the last mentioned group and the rules of English, as well as Greek, demand that "them" and "they" of verse 4 be understood as the "apostles" of verse 2.
The purpose of this baptism was to equip the apostles for their special task (John 16:13; Acts 1:8; Hebrews 2:4). They were to receive and to instruct the church in the New Covenant. They would be led into all truth, and would have the ability to: l. pen the "Word of God" 2. speak in tongues (foreign languages without prior training) 3. perform miraculous works of healing on those with and without faith 4. raise the dead and 5. pass on one of these spiritual gifts through the "laying on of their hands", but the recipient of a gift could not pass it on unto others. Thus, after the apostles died and those who had received a spiritual gift from them, the Baptism of the Holy Spirit "signs" ceased, and Paul in I Corinthians 13:8-10 said that they would. That should settle it, shouldn't it? Again in II Corinthians 12:12, he refers to the "signs of an apostle."
Let us now turn in our Bibles back to Mark 16, where we began. Notice what is transpiring in verse 14. Jesus is reprimanding the "eleven" (this was His twelve apostles, minus Judas who had committed suicide) for their unbelief. The next two verses tell of Jesus issuing the "Great Commission". The pronoun "He" (NIV "whoever"; v.16) is singular. This refers to any individual who accepts the Savior.
Then, in verses 17 and 18, the pronouns are switched to the plural form, "them" (NIV "those" and "they"). What was the last group (plural) mentioned? The answer is the "eleven" apostles in verse 14. Thus, the apostles only could do these "signs" and not every Christian. The book of Acts gives examples of each of these signs worked by an apostle, with exception of the fourth. Read Acts 2:4; 16:18; 28:5,7,8. Even though Eusebius (Third Century Church Historian) mentioned that this did happen to Justus Barsabas (cf. Acts 1:23) in Eusebius (III,39).
Newsweek, April 23, 1973, carried the article on two individuals in Carson Springs, Tennessee, who thought they would "prove their faith" by drinking a potent mixture of strychnine and water while the congregation chanted, "Praise God." Following the service, the two men doubled up in an agony of convulsive twitching and by morning both were dead. They were buried at snake handling funeral ceremonies, with their Bibles laying upon their chests, and opened to Mark 16:16-18.
Let us not be "fooled" by those who do not rightly divide the Word of God. The "signs" were to confirm or prove the Word, which the apostles preached (Mark 16:20; II Corinthians 12:12; Hebrews 2:4). If such "signs" existed today from God, then we could very well expect further revelation. Thus, if God would sent further revelation, then the Bible would be outdated by it. To believe in present day revelation is anti-scriptural (see Galatians 1:8,9; Jude 1:3; Revelation 22:18,19).
Why do many today desire those things which were not meant for us? This is to say, “God, I am not satisfied with just the Bible, speak to ME in some special way." The Bible says that the miracles of Christ are recorded so that we might obtain faith (John 20:30,31). The Bible says that we obtain faith by hearing of these miracles, through the Word of God (Romans 10:17), not through seeing them today. Those who have gotten all excited about the "signs" mentioned in Mark 16:17,18, and insist on them in our day, should realize the error of their way by thinking about the snakes and strychnine.
From a study of the Baptism of the Holy Spirit, one will learn that the promise was only to the Apostles. However, in Acts 10,11, we find an exception made for Cornelius. The was for a special reason. That reason being to show the prejudiced Jews that God wanted the Gentiles saved also. Then we also find that the apostle Paul received the baptism. Just when, it is not stated. Possibly during his three year duration in Arabia (Galatians 1:15-18). But, it is certain that he was an apostle, called out of due time, and that he had the powers of an apostle (I Cor. 9:1); 15:8; Romans 1:11).
We might note that God's Word teaches that there are only four groups who have power to do these signs: 1. Christ (Matthew 9:6; Acts 2:22); 2. Apostles (Acts 1:1-5; II Corinthians 12:12); 3. Disciples who had the Apostle's hands laid upon them (Acts 6:5-8; 8:5-18); 4. Anti-Christ (II Thessalonians 2:9).
Brethren, may we be on guard against those seeking after "signs". Might we give heed unto the words of the inspired apostle Paul, "Then we will no longer be like children, forever changing our minds about what we believe because someone has told us something different, or had cleverly lied to us and made the lie sound like the truth." (Ephesians 4:24, Living Bible).