Reuben

Boyd’s Bible Dictionary:

(behold a son!). Eldest son of Jacob and Leah (Gen. 29:3232And Leah conceived, and bare a son, and she called his name Reuben: for she said, Surely the Lord hath looked upon my affliction; now therefore my husband will love me. (Genesis 29:32)). Lost his birthright through crime (Gen. 35:22; 49:3-422And it came to pass, when Israel dwelt in that land, that Reuben went and lay with Bilhah his father's concubine: and Israel heard it. Now the sons of Jacob were twelve: (Genesis 35:22)
3Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power: 4Unstable as water, thou shalt not excel; because thou wentest up to thy father's bed; then defiledst thou it: he went up to my couch. (Genesis 49:3‑4)). Tribe numerous and pastoral, and settled east of Jordan (Num. 1:20-2120And the children of Reuben, Israel's eldest son, by their generations, after their families, by the house of their fathers, according to the number of the names, by their polls, every male from twenty years old and upward, all that were able to go forth to war; 21Those that were numbered of them, even of the tribe of Reuben, were forty and six thousand and five hundred. (Numbers 1:20‑21); Josh. 13:15-2315And Moses gave unto the tribe of the children of Reuben inheritance according to their families. 16And their coast was from Aroer, that is on the bank of the river Arnon, and the city that is in the midst of the river, and all the plain by Medeba; 17Heshbon, and all her cities that are in the plain; Dibon, and Bamoth-baal, and Beth-baal-meon, 18And Jahazah, and Kedemoth, and Mephaath, 19And Kirjathaim, and Sibmah, and Zareth-shahar in the mount of the valley, 20And Beth-peor, and Ashdoth-pisgah, and Beth-jeshimoth, 21And all the cities of the plain, and all the kingdom of Sihon king of the Amorites, which reigned in Heshbon, whom Moses smote with the princes of Midian, Evi, and Rekem, and Zur, and Hur, and Reba, which were dukes of Sihon, dwelling in the country. 22Balaam also the son of Beor, the soothsayer, did the children of Israel slay with the sword among them that were slain by them. 23And the border of the children of Reuben was Jordan, and the border thereof. This was the inheritance of the children of Reuben after their families, the cities and the villages thereof. (Joshua 13:15‑23)). Idolatrous, averse to war, carried captive by Assyria (Judg. 5:15-1615And the princes of Issachar were with Deborah; even Issachar, and also Barak: he was sent on foot into the valley. For the divisions of Reuben there were great thoughts of heart. 16Why abodest thou among the sheepfolds, to hear the bleatings of the flocks? For the divisions of Reuben there were great searchings of heart. (Judges 5:15‑16); 1 Chron. 5:2626And the God of Israel stirred up the spirit of Pul king of Assyria, and the spirit of Tilgath-pilneser king of Assyria, and he carried them away, even the Reubenites, and the Gadites, and the half tribe of Manasseh, and brought them unto Halah, and Habor, and Hara, and to the river Gozan, unto this day. (1 Chronicles 5:26)).

Concise Bible Dictionary:

The firstborn of Jacob and of Leah, and head of one of the twelve tribes. The territory they possessed also bears his name. He saved the life of Joseph when his brothers thought to kill him, and when they went to buy corn in Egypt, he offered to be responsible for Benjamin’s safety. Jacob, when blessing his sons, said, “Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power: unstable as water, thou shalt not excel; because thou wentest up to thy father’s bed; then defiledst thou it” (Gen. 49:3-43Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power: 4Unstable as water, thou shalt not excel; because thou wentest up to thy father's bed; then defiledst thou it: he went up to my couch. (Genesis 49:3‑4)). This speaks of failure in the firstborn, and implies loss of his birthright. (Joseph, type of Christ separated from His brethren, had the birthright.) Moses, when he blessed the tribes (showing more their relationship with God according to His government) said, “Let Reuben live, and not die: and let not his men be few” (Deut. 33:66Let Reuben live, and not die; and let not his men be few. (Deuteronomy 33:6)). Reuben entered Egypt with his four sons, Hanoch, Phallu, Hezron, and Carmi (Gen. 46:99And the sons of Reuben; Hanoch, and Phallu, and Hezron, and Carmi. (Genesis 46:9)).
At the Exodus the tribe numbered 46,500 men fit to go to war; and at the close of the wanderings they had decreased to 43,730. At their request, Reuben had their possession on the east of the Jordan, because it was “a place for cattle.” It extended northward from the river Arnon about 25 miles, where it joined the possession of Gad.
The Reubenites do not appear to have taken any prominent part in the struggles under the Judges; they had “great thoughts of heart,” but remained with their flocks (Judg. 5:15-1615And the princes of Issachar were with Deborah; even Issachar, and also Barak: he was sent on foot into the valley. For the divisions of Reuben there were great thoughts of heart. 16Why abodest thou among the sheepfolds, to hear the bleatings of the flocks? For the divisions of Reuben there were great searchings of heart. (Judges 5:15‑16)). They made inroads upon the Bedouin tribes: being on the border of the wilderness doubtless this was unavoidable if they were to live in peace and safety (1 Chron. 5:9-10, 189And eastward he inhabited unto the entering in of the wilderness from the river Euphrates: because their cattle were multiplied in the land of Gilead. 10And in the days of Saul they made war with the Hagarites, who fell by their hand: and they dwelt in their tents throughout all the east land of Gilead. (1 Chronicles 5:9‑10)
18The sons of Reuben, and the Gadites, and half the tribe of Manasseh, of valiant men, men able to bear buckler and sword, and to shoot with bow, and skilful in war, were four and forty thousand seven hundred and threescore, that went out to the war. (1 Chronicles 5:18); &c). The Reubenites, with the others on the east of the Jordan, went after the gods of the heathen, and Jehovah cut them short by Hazael, king of Syria (2 Kings 10:32-3332In those days the Lord began to cut Israel short: and Hazael smote them in all the coasts of Israel; 33From Jordan eastward, all the land of Gilead, the Gadites, and the Reubenites, and the Manassites, from Aroer, which is by the river Arnon, even Gilead and Bashan. (2 Kings 10:32‑33)). Afterward by Pul and Tiglath-pileser they were carried away captive unto Halah, Habor, Hara, and to the river Gozan (1 Chron. 5:2626And the God of Israel stirred up the spirit of Pul king of Assyria, and the spirit of Tilgath-pilneser king of Assyria, and he carried them away, even the Reubenites, and the Gadites, and the half tribe of Manasseh, and brought them unto Halah, and Habor, and Hara, and to the river Gozan, unto this day. (1 Chronicles 5:26)).
The east of the Jordan was a place of danger. Remaining there was a type of a Christian stopping short of the place of nearness God has given him—not realizing his death and resurrection with Christ, and his true place in the heavenlies.

Jackson’s Dictionary of Scripture Proper Names:

see ye, a son