God intended Israel to be " a Kingdom of priests" (Ex. 19:6). “All the people of Israel” were the builders of the spiritual house of God, i.e. His people (Acts 4:10,11). All Israel were to lay their hands on the Levites to show that they were truly Israel’s representatives (Num. 8:10). When Israel were rejected, they were told that they as a nation could no longer be God’s priest (Hos. 4:6). By baptism, we become spiritual Israel; and this idea is relevant to us too. Peter picks up these words in Exodus and applies them to every one of us: " Ye also are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices" (1 Pet. 2:5,9). The Lord Jesus is a King-priest after the order of Melchizedek (Heb. 6:13-18; Ps. 110:4); and through being in Him, we share this position. Through what He achieved for us on the cross, we have been made now king-priests, with the future hope of reigning on earth (Rev. 1:6; 5:10). The religious world around us puts great emphasis upon having a system of priests and pastors. Christians are almost the only group who don't have such a system. To me, the fundamental reason for this is a Biblical one: quite simply, according to plain Bible teaching, we're all priests.
The duty of the priests under the Old Covenant was to maintain true understanding of God's word, witness this to the world around them, and teach it to their brothers and sisters in Israel (Mal. 2:7). Although there was a special priesthood, it was clearly God's intention that all Israel should be like priests; they were to be a " Kingdom of priests" (Ex. 19:6). Israel were all “saints”, and yet saints and priests are paralleled in passages like Ps. 132:16. Israel in the wilderness had clothes which didn’t wear out- just as the Priestly clothes didn’t, and were handed down from generation to generation (so Ex. 29:29 implies). People from all nations who want to become part of God’s people in the Millennium will have to join / levite themselves to Him; they will enter into a priestly covenant, in order to be counted as part of His people. Being His nation and being a priest are connected. Israel were to teach every man his neighbour and brother, saying, Know the Lord (Heb. 8:11). God therefore saw all Israel as represented by the priests (Hos. 4:9; Is. 24:2; Jer. 5:31; 8:10); He says in Hag. 2:12-14 that He saw all Israel as defiled priests. Hos. 4:1,6, in a passage directed to all Israel rather than just the priests (cp. 5:1), warns the whole nation that they can no longer be God's priest, because of their sins. There are many hints throughout the Old Testament that God encouraged all His people to behave like priests. The early chapters of Proverbs exhort the average Israelite to love God's Law, study it, talk about it to their neighbours and children...all of which was priestly behaviour. They were all priests. The language of the priesthood is applied in those chapters to the normal, Bible-loving Israelite. For example, " the priests lips should keep knowledge" (Mal. 2:7); but the average Israelite was encouraged to study the Law for himself, " that thy lips may keep knowledge" (Prov. 5:2) (1). Indeed, the principle of Nazariteship (explained in Num. 6) encouraged the average Israelite, regardless of his tribe, to in some way aspire to the High Priesthood. He could grow his hair long to imitate the High Priestly mitre, and he could chose to have the same commands concerning defilement by the dead and eating vine-products apply to him, as applied to the High Priest. The Lord applied this to all His followers, when He told the man who wished to bury his father to not do so, but engage instead in His work (Lk. 9:59,60). This would have sent the Jewish mind back to Lev. 21:1-11, where the High Priest could not be distracted from his service even by the death of his father.
When we come to the New Testament, there is no equivalent of the priestly system of the Old Covenant. This was a big change for the early Jewish Christians. Because of this, and in order to establish the Christian church, God temporarily gave the miraculous gifts of the Holy Spirit to some members of the early church. Those with the gift of speaking God's word or acting infallibly in their judgments naturally had to be treated with great respect; they were speaking and judging on God's behalf. It seems that each of the early ecclesias had a Spirit-gifted eldership, which Paul and Peter exhorts should be respected. But now the Spirit gifts have been withdrawn; they have been replaced by the dispensation of the completed word of God, to which we all have access. For we're all priests.
(1) Other examples include the way in which Proverbs stresses that the man who loves wisdom will be able to judge wisely (2:9; 31:9). Yet it was the priests who were the judges of Israel (Dt. 19:17), they were the ones to whom hard cases were brought. Yet Proverbs implies all could act as priests. " To do justice and judgment is more acceptable (a word elsewhere used concerning the priests' service, Dt. 21:5) than (the offering of) sacrifice" (Prov. 21:5). Loving wisdom would give the ordinary Israelite a crown on his head (4:9), alluding to the High Priestly crown (Ex. 29:6; Zech. 6:11). Proverbs constantly urges Israel not to forget the Law (e.g. 2:6)- but the priests did just this (Hos. 4:6). There is good reason to think that Proverbs is a commentary on the Mosaic Law.