From BiblePortal Wikipedia

Watson's Biblical & Theological Dictionary [1]

The Rechabites, though they dwelt among the Israelites, did not belong to any of their tribes; for they were Kenites, as appears from  1 Chronicles 2:55 , where the Kenites are said to have come of "Hemath, the father of the house of Rechab." These Kenites, afterward styled Rechabites, were of the family of Jethro, otherwise called Hobab, whose daughter Moses married; for "the children of the Kenite, Moses's father-in-law," it is said, "went up out of the city of palm trees with the children of Judah, and dwelt among the people,"  Judges 1:16; and we read of "Heber the Kenite, who was of the children of Hobab, the father-in- law of Moses, who had severed himself from the Kenites," or from the bulk of them who settled in the tribe of Judah, "and pitched his tent in the plain of Zaanaim,"  Judges 4:11 . They appear to have sprung from Midian, the son of Abraham by Keturah,  Genesis 25:2; for Jethro, from whom they are descended, is called a Midianite,  Numbers 10:23 . Of this family was Jehonadab, the son of Rechab, a man of eminent zeal for the pure worship of God against idolatry, who assisted King Jehu in destroying the house of Ahab, and the worshippers of Baal,  2 Kings 10:15-16;  2 Kings 10:23 , &c. It was he who gave that rule of life to his children and posterity which we read of in  Jeremiah 35:6-7 . It consisted of these three articles: that they should drink no wine; that they should neither possess nor occupy any houses, fields, or vineyards; that they should dwell in tents. This was the institution of the children of Rechab; and this they continued to observe for upward of three hundred years, from the time of Jehu to that of Jehoiakim, king of Judah, when Nebuchadnezzar coming to besiege Jerusalem, the Rechabites were obliged to leave the country and take refuge in the city. In Jeremiah 35, there is a promise made to this people, that Jonadab, the son of Rechab, should not want a man to stand before the Lord; that is, that his posterity should not fail: and to this day this tribe is found among the Arabians of the desert, distinct, free, and practising exactly the institutions of Jonadab, whose name they bear, and of whose institutions they boast. This is a remarkable instance of the exact fulfilment of a minute and isolated prophecy. See Beni Khaibir .

Morrish Bible Dictionary [2]

Descendants of Rechab, the father of Jonadab. The account of these people is given by themselves: they abstained from wine, and they did not build houses, nor sow seed. Being nomads they did not plant vineyards, nor had any; but all their days they dwelt in tents. Though called Rechabites, they trace their mode of life to what their ancestor Jonadab had commanded. When compelled to dwell in Jerusalem for fear of the Chaldeans and Syrians, Jeremiah called them together and offered them wine; but they refused to drink any, and gave the above explanation.

God instructed Jeremiah to hold up the obedience of the Rechabites as an example to the men of Judah. These men faithfully obeyed their father, whereas Judah had not obeyed their God . It was said of them that because of their faithfulness to their father's commands Jonadab should not want a man to stand before God for ever. The Rabbis interpret this to signify that they should minister in the sanctuary, and say they became united to the Levites; but we find nothing of this in scripture.  Jeremiah 35:1-19 . Travellers in the East have met with people who trace their origin to Rechab, and who appeal to the scripture as a proof of God having preserved them. There are still about 60,000 of them, dwelling in tents in the oases of the desert.

American Tract Society Bible Dictionary [3]

Scripture acquaints us,  Jeremiah 35:2-11 , that Jonadab son of Rechab, in the time of Jehu king of Israel; laid an injunction on his posterity not to drink wine, not to build houses, not to plant vineyards, to have no lands, and to dwell in tents all their lives. This they continued to observe for above three hundred years; but in the last year of Jehoiakim king of Judah, Nebuchadnezzar coming to besiege Jerusalem, the Rechabites were forced to take refuge in the city, though still lodging in tents. During this siege, Jeremiah received orders from the Lord to invite them into the temple, and to offer them wine to drink. They refused to partake of it; and their fidelity to their father's injunction was a severe reproof to the Jews; and the divine promise concerning the perpetuity of the family,  Jeremiah 35:19 , was undoubtedly fulfilled, though it may now be impossible to distinguish temm, as some profess to do, among the tribes of Central Arabia.

People's Dictionary of the Bible [4]

Rechabites ( Rĕ'Káb-Îtes or Rĕk'Ab-Îtes ). A Kenite tribe descended from Rechab. Jonadab, one of their chiefs, laid an injunction on his posterity to drink no wine, to build no houses, but to dwell in tents. This injunction they obeyed fully for 300 years; but upon the Chaldean invasion they were forced to quit the open country and live in Jerusalem.  Jeremiah 35:1-19. Afterwards they probably withdrew into the desert. For their obedience a promise was given them that their family should never be extinct. And accordingly, at the present day, there is an Arabian tribe who claim a descent from Rechab, and profess a modified Judaism.

Easton's Bible Dictionary [5]

 Judges 1:16 1 Samuel 15:6 Nehemiah 3:14  1 Chronicles 2:55

Holman Bible Dictionary [6]

 2 Kings 10:15-17 Jeremiah 35:1

Ricky L. Johnson

Kitto's Popular Cyclopedia of Biblial Literature [7]

Re´chabites. The tribe or family of Kenites, whom Jonadab, the son of Rechab, subjected to a new rule of life; or rather bound to the continued observance of ancient usages which were essential to their separate existence, but which the progress of their intercourse with towns seemed likely soon to extinguish. By thus maintaining their independent existence as a pastoral people, they would keep themselves from being involved in the distractions and internal wars of the country, would be in no danger of becoming objects of jealousy and suspicion to the Israelites, and would be able at all times to remove from a country in which they were strangers. The Rechabites found so much advantage in these rules, that they observed them with great strictness for about 300 years, when we first become aware of their existence. Jeremiah put to the proof their adherence to their founder's rules, and they stood the test .

What eventually became of the Rechabites is not known. The probability is that, when they found themselves no longer safe among the Hebrews, they withdrew into the desert from which they at first came, and which was peopled by men of similar habits of life, among whom, in the course of time, they lost their separate existence.

The Nuttall Encyclopedia [8]

A tribe of Arab origin and Bedouin habits who attached themselves to the Israelites in the wilderness and embraced the Jewish faith, but retained their nomadic ways; they abstained from all strong drink, according to a vow they had made to their chief, which they could not be tempted to break, an example which Jeremiah in vain pleaded with the Jews to follow in connection with their vow to the Lord (see Jer. xxxv.).