We notice that the Feast in Jerusalem, to which the Lord Jesus went on this occasion, is called here the Passover of the Jews. It is no longer the Passover of the Lord (Exodus 12:27). After His death it was reduced to a Jewish religious festival, a ritual only. The Person represented by the Passover had already come: "Indeed Christ, our Passover, was sacrificed for us.” (1 Corinthians 5:7).
At that time Passover was celebrated annually in the temple in Jerusalem. It was one of three annual feasts all of which demanded the men's attendance, the other ones being the Feast of Pentecost and the Feast of Tabernacles. The Feast of Passover commemorated the liberation of the Jews from the slavery in Egypt (Exodus 12:1-13) and it began approximately on the fourteenth day of April in our calendar, lasting seven days altogether. Passover proper was celebrated on the initial day, followed by the Feast of Unleavened Bread.
Many Jewish families travelled from the whole world to Jerusalem during those Feasts. During Passover, therefore, the area of the temple was always packed with thousands of visitors in addition to the inhabitants of the city.
All Israelites twenty years old and upward had to pay annually in the sacred treasury of the temple half a shekel as an offering to the Lord (Exodus 30:13-15), and this with the old traditional Hebrew coin of this exact value. People were also required to offer animals in sacrifice of their sins. Many could not bring their animals with them because they came from afar, or because they didn't have animals in the perfect condition required.
There was, therefore, great demand for half shekel coins as well as for animals for sacrifice and holocaust on the Feast of Passover. To facilitate the trade, the religious leaders allowed changers of money and salesmen to set up their benches and stands in the Gentiles' sector of the temple, for rent. It was lucrative for the merchants and profitable for the priests, at the expense of those that came to offer sacrifice. The temple of God was being used in an inadequate manner, and the pursuit of material gain and the use of greedy practices prevailed. The House of God had turned into a type of commodities exchange or street market.
The Lord was angry at this and, having made a whip of cords, He drove them out of the temple with their animals, and poured out the changers' money and overturned the tables, saying to those who sold doves, "Take these things away! Do not make My Father's house a house of merchandise!" because they were making a mockery of the house of God. At the end of His ministry, approximately three years later (Matthew 21:12-17; Mark 11:12-19; Luke 19:45-48), he repeated this cleaning, because profit motivated those people more than the desire to preserve the holiness of the temple.
God always warned His people against the use of His worship for their own enrichment. What the Lord did on those occasions was not cruel or unfair, but was only the manifestation of His holiness and justice, which reminded His disciples of the verse in Psalm 69:9 “... zeal for Your house has eaten me up”. This psalm is mentioned seventeen times in the New Testament and it is one of the six psalms most quoted in the New Testament (it is mentioned again in John 15:25 and 19:28-29 - the other psalms that frequently are mentioned are 2, 22, 89, 110 and 118).
The Jews (understood here to be the religious persons who administered the temple) who considered themselves "owners" of the temple, were indignant: as they had not been consulted, they demanded that the Lord gave them proof that He had authority to do what He had done.
His answer astonished them, for He declared: “Destroy this sanctuary, and in three days I will raise it up."(YLT) Not paying sufficient attention to the words that He used, they understood that the sanctuary would be the temple from which the Lord Jesus had just expelled the merchants and money-changers. This was the temple initially built by Zerubbabel 500 years before, ruined by the enemies' action and neglect by the Jews, but being rebuilt by Herod starting 46 years before (completed in 65 AD, but the temple was completely destroyed five years later by the Romans, as had been predicted by the Lord according to Luke 19:41-44).
In the understanding of the Jews, this power that Lord Jesus claimed to have would be a blasphemy. It was of this that they accused Him in His judgement before the chief priests and of the Sanhedrin, who accepted a testimony from false witnesses who distorted His words, declaring that He had said: I am able to throw down the sanctuary of God, and after three days to build it (Matthew 26:61).
In fact the word that He used, translated as “(you) destroy” is "luo" which can also mean “untie” and the word that He used in verse 19 and the Jews repeated in the verse 20 is “naos” which refers to the inner sanctuary of the temple (in verses 14 and 15, the word used for “temple” is “hieron” which means the whole building: it includes the external court that had been contaminated and needed purifying, not just the internal sanctuary). The word “naos” is used in 1 Corinthians 6:19 where we read that the believer's body is the “sanctuary” of the Holy Spirit.
The word translated as “build it” is “egeiro”, which also means “wake it up” Romans 13:11) and is also translated as “raise the dead” (or “raise of the dead”) in other places (Acts 26:8, 2 Corinthians 4:14, Hebrews 11:19). When He said: “Untie this sanctuary and in three days I will raise it from the dead”, it meant that they would "untie" His spirit (by death from His human body) and the Lord Jesus Himself would raise it (His body) from death after three days (Matthew 12:39-41, 16:4). Just as the Lord used parables to confuse the sceptics, Jesus Christ would have used that ambiguous expression to confuse His enemies. His listeners didn't take notice that He was greater than the temple (Matthew 12:6)!
Like the Jews, the disciples didn't understand His statement. Only after the resurrection did they remember it, then they believed in the Scriptures: wounded and bruised (Isaiah 53:5), cut off (Daniel 9:26), His soul would not be left in Sheol, nor would His body see corruption (Psalm 16:10), and they understood its high meaning. The high meaning was that, having Christ fulfilled so perfectly His prediction, this turned to be one of the strongest evidences of His claim of being God: only God could accurately say that He would raise the body from the dead three days after dying!
During the Feast, the Lord provided miraculous signs that caused many people to see and believe in His name. But it was not a saving faith: they only accepted the legitimacy of the miracles that they saw. Although they believed in His power, which they witnessed, He didn't trust in them because He knew their human nature (Jeremiah 17:9), and He knew that their faith was superficial. Many of those people who said they believed in the Lord Jesus on that occasion would possibly be the same that cried out “crucify Him” later. It is easy to believe when many others think the same way, giving a feeling of wellbeing, which really is false security.
Even today, many that say they have faith in Jesus Christ don't go beyond believing in the facts of the Gospel. Unless they trust the Lord Jesus as their Saviour, Who gave His life for their sins and for their justification, He being their only hope for salvation from eternal condemnation for their sins, and they are prepared to declare their faith in the Lord Jesus Christ even if they run the risk of death from His enemies, they don't really have saving faith.