Question:
In Mark 16:15-20 it says certain signs will accompany those who believe. Should it be the same today: should these signs accompany us if we believe and are saved? Hebrews 13:8 says Christ is the same yesterday, today, and forever. If Christ is the same shouldn’t His teachings be the same? Malachi 3:6 says the Lord does not change.

Answer:
Before we consider the first question dealing with whether or not signs should accompany believers today, let’s try to answer the second question: “If Christ is the same, shouldn’t His teachings be the same?” I would like to show from Scripture that this reasoning is simply not true, and therefore, it is not a true premise upon which one can conclude that supernatural signs must accompany all who believe up to the present time.

In the so-called “Sermon on the Mount,” we have the Lord Jesus teaching the multitudes (Matthew chapters 5-7). In 5:21 He refers to the teachings they had received under the Mosaic Law with the expression: “Ye have heard that it was said by them of old time,” and He then goes on to say to them, “But I say unto you,” which is followed by a new teaching which either changes or adds to the former teaching received under Moses. He does this no less than six times (see 5:21, 22, 27, 28, 31, 32, 33, 34, 38, 39, 43, 44).
Let’s look at verses 43 and 44: “Ye have heard that it hath been said, Thou shalt love thy neighbor, and HATE THINE ENEMY. But I say unto you, LOVE YOUR ENEMIES, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you.” This is quite a change in God’s teaching, wouldn’t you say!? To go from hating one’s enemy to loving him is about as drastic a change as can be.
Under ACTION the Law, God taught His people to hate their enemies and we know from Scripture that He even had them destroy their enemies without mercy at times (see 1 Samuel 15:1-3 for an example of this). But when Christ came, He came “full of grace and truth” (John 1:14, 17), and just as He manifested God’s grace to His enemies, He would have His disciples display the same grace to their enemies. So we see that God can, and does, change His teachings at times, according to His purposes for mankind. I might just add here that after the rapture of the church to glory, the Jews who are saved will once again resort to the teaching of hating their enemies. Many of the Psalms speak of the faithful remnant of Jews who will go through the tribulation and they will be praying for the destruction of their enemies (see Psalms 74 and 79 as examples of this, along with Revelation 6:9, 10). So to reason that because Christ does not change, His teachings must remain the same, is faulty logic. Thus, we cannot use that as a reason for saying that, because Christ taught that certain signs would follow them that believe, it must be true for all believers at all times.
I believe the “key” to answering the first question lies in Mark 16:20: “And they went forth, and preached everywhere, the Lord working with them, and CONFIRMING THE WORD WITH SIGNS FOLLOWING.” Supernatural signs were given by God to CONFIRM (make firm, establish, make secure) the Word. This was the chief purpose for the signs. A “sign” is something that points someone to something; in this case the signs were used to point people to the Word.
In Hebrews 2:3, 4 we read, “How shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard Him; GOD ALSO BEARING WITNESS, BOTH WITH SIGNS AND WONDERS, AND WITH DIVERS MIRACLES.” Here is another passage which speaks of SIGNS being given to confirm the Word. This “so great salvation” which the Lord spoke of, and then those who heard Him, was accompanied by signs which would serve to authenticate the Word spoken. Why was there the need of signs? I would like to offer two reasons:

(1)  God had not spoken to man for 400 years (His last word was through the prophet Malachi) and after that much time one would be very leery of anyone professing to be inspired of God and proclaiming His Word. But with supernatural signs accompanying the message, God could draw attention to the fact that this was from Him.

(2)  The new message (spoken of as “so great salvation”) that God was going to give to men was going to be very hard to believe. The truths of Christianity were, in many cases, in direct contrast to the truths God has formerly given in Judaism, and God would graciously use signs to wean His people of old from that former teaching. Think of the Jew who had been raised under the Law, with all of its penalties for those who would break it, now hearing a message which, instead of demanding something from him and punishing him for not producing what the Law demanded, spoke of God’s giving His Son to redeem them who were under the Law. And think of the heavenly blessings and destiny promised to the one who believed on God’s Son. This was in direct contrast to the Jew’s portion under the Law, for his blessings and future promises were all earthly. So we see that this new message concerning Christ was going to be hard to believe, especially for a pious Jew who had been raised under Law. How good of God to confirm His Word with signs!

In Acts 6:7 we read, “And 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” (see also Acts 12:24; 19:20). These verses clearly reveal that the Word of God was bearing precious fruit, thus the signs that accompanied the Word were indeed used of God mightily to “confirm the Word.”I will close my thoughts on this subject by referring to two facts. (1) As we read the book of Acts it becomes obvious that “signs” were very prominent in the beginning, but as we read on they are hardly mentioned. In the last chapters of this great historical book they disappear altogether, except for one case recorded in Acts 28:1-9. (2) In the later epistles that Paul wrote, we hear nothing about signs and miracles. Not one syllable is uttered regarding tongues or any of the other signs mentioned in Mark 16. But we do hear of Paul’s companion, Epaphroditus, being “sick nigh unto death” (Philippians 2:25-30). And although he was later healed, we have nothing to lead us to believe that Paul or anyone else healed him. Instead, we read that “God had mercy on him” (v. 27). In 1 Timothy 5:23 Paul encourages Timothy to use a little wine for medicinal purposes. And in Paul’s very last epistle we read of Paul leaving Trophimus sick at Miletum (2 Timothy 4:20). Surely these instances are instructive, and the unbiased reader is forced to conclude that signs, such as healing, did indeed cease after their intended purpose (which was to “confirm the Word”) was over.