Deuteronomy 33:6

Let Reuben live, and not die
As a tribe, continue and not be extinct, though they should not excel, because of the sin of their progenitor; and it may have a special regard to the preservation of them, of their families on the other side Jordan, while they passed over it with their brethren into Canaan, and of them in that expedition to help the other tribes in the conquest of the country and the settlement of them in it; which Jacob by a spirit of prophecy foresaw, and in a prayer of faith petitioned for their safety: all the three Targums refer the words to a future state, as a wish for them, that they might live and enjoy an eternal life, and not die the death of the wicked in the world to come; and which they call the second death, and from whom the Apostle John seems to have borrowed the phrase, ( Revelation 2:11 ) ( Revelation 20:6 ) ( 21:8 ) ; Reuben signifies, "see the Son"; and all that see the Son of God in a spiritual manner, and believe in him with a true faith, as they live spiritually now, shall live eternally hereafter, and never die the second or eternal death; on them that shall have no power, see ( John 6:40 ) ;

and let [not] his men be few;
or, "though his men be few?" as Bishop Patrick chooses to render the words, and as they will bear, (w) , "vau", being sometimes so used, of which Noldius ^F8 gives instances; and the number of men in this tribe were but few in comparison of some others; and so those that see the Son of God and believe in him are but a small number; for all men have not faith. ( 2 Thessalonians 3:2 )