Genesis 49:4
Unstable 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. Unstable 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.
With his children gathered around him at his death, Jacob spoke under the Spirit to lay open their past and future and reveal God's purposes for them. Reuben was the firstborn with the dignity and power of the beginning of his father's strength, yet he had grievously transgressed God's law by defiling his father's bed. For that sin he was declared unsteady and changeable, disqualified from the preeminence and honors of the birthright so that he would not rise above his brothers. That sentence was fulfilled when his tribe never attained eminence in Israel, remaining smaller than Judah, Joseph, or Dan and falling among the first into captivity. The same lack of steadiness still keeps people from rising, for without inward rectitude, fixed principle, and persevering self-denial toward God they yield easily to temptation and cannot truly succeed or bear fruit to His glory.
Jacob's Dying Prophecy
Genesis 49:4 belongs to Jacob's dying blessing and last counsel, spoken with his children gathered around him when the Spirit of the Lord rested upon him to lay open their past lives and future history, to reveal God's purposes, and to reach far into the future. It was not spoken from an unforgiving or resentful paternal spirit, for he had forgiven his children and loved them to the last, and by natural affection would have spoken only love and tenderness. God elevated his mind above natural feeling, with angels around him in his last hours and the power of grace shining upon him, so that under inspiration and the spirit of prophecy he uttered painful truth although painful. In this way the word showed that God by no means sanctions cruelty or wickedness.
Reuben was the firstborn, the might and beginning of Jacob's strength with excellency of dignity and power, and he had no hand in selling Joseph. Yet he had previously grievously sinned in a corrupt course transgressing God's law by a grave crime in Jacob's family. That crime was lying with his father's concubine and defiling his father's bed, going up to his father's bed and to his couch. This judgment was spoken under inspiration despite Jacob's love for Reuben, because Reuben had so sinned before Joseph was sold.
Because of that sin Reuben, though firstborn, was unstable as water and would not excel. He was thereby disqualified and made unworthy of the firstborn's blessing, losing the preeminence with its privileges and honors of the birthright. The sentence was fulfilled in that the tribe of Reuben never attained eminence in Israel. It remained less numerous than Judah, Joseph, or Dan and was among the first carried into captivity. While severe, his prophetic word was not as gloomy as the words to Simeon and Levi.
Instability Warns Today
Unstable as water describes those who have no inward rectitude or fixed principles, who yield easily to temptation and lack strength to refuse to do wrong, and who therefore cannot excel because they have no firm moral foundation. The water image pictures a fickle person without decision who cannot be truly successful, while continued perseverance increases usefulness and the ability to work effectively and bear fruit to God's glory. The same instability that prevents excelling marks those who are far from God and unwilling to deny themselves or sacrifice for Him.
Instability describes a spiritually unsteady character that will not excel, and if such persons are saved at all it will be by at last obeying earlier warnings they had despised rather than by continuing to resist the Spirit of grace. Weakness as water also belongs to those who profess truth only because others accepted it and cannot explain their reasons, who without examining motives, understanding the principles behind their actions, and building on personal conviction lack strength and fail to live by principle, including in health reform and changing the diet. The water image of instability and weakness that prevents excelling applies to those who remain spiritually weak despite access to strength from heaven, yet with God's help they can grow in spiritual power and character until envy, pride, malice, jealousy, and selfishness are replaced by the graces of the Spirit.
Being unstable as water applies to those who adopt worldly fashions and customs in dress, showing lack of steadfastness and consistency in spiritual growth so that piety loses its vitality. It denotes lack of steadiness and victory, as seen in a man who had not kept the Sabbath and lacked divine help to overcome evil habits and personal besetments. The church itself becomes weak as water and loses strength and standing when its members act inconsistently and carelessly, betraying confidence and harming one another through gossip, exaggeration, and unguarded speech. Comparison to water likewise applies to a church made weak by faultfinding, where criticism stirs up the church and weakens its members, while the faultfinder helps Satan's work of accusation instead of building the church up.