1 Chronicles 28:20
And David said to Solomon his son, Be strong and of good courage, and do it: fear not, nor be dismayed: for the LORD God, even my God, will be with thee; he will not fail thee, nor forsake thee, until thou hast finished all the work for the service of the house of the LORD.
The words belong to David's final charge concerning the temple, spoken to Solomon his son as acknowledged successor to the throne, who was appointed to build it. David's part was to advise, counsel, and encourage Solomon, while Solomon himself was to carry out the task God had assigned him. God's work may pass to others whom He qualifies, and experienced workers should help rather than hinder those who take it up.
Solomon felt daunted by the greatness of the plans and the weight of his responsibilities in building the temple and governing God's people. David therefore urges him to be strong and of good courage, to act without fear or dismay, and to carry the work through to completion, since the greatness of the plans is no reason for discouragement. The ground for that courage is that the Lord God will be with Solomon, will not fail or forsake him, but will sustain and help him and give him courage until all the work for the service of the house is finished.
The charge grows out of David's own hard experience of departing from God, feeling condemnation under God's law and reaping the fruits of transgression, and out of his earnest desire that Solomon obey God's law and shun the sins that weakened David's authority, embittered his life, and dishonored God. Standing firm in such an exalted station requires humility of heart, constant trust in God, and unceasing watchfulness, because temptation surely besets exalted station and prominent leaders are a special mark for Satan. The same charge is addressed to men in positions of trust in God's work today, whose day of test and trial is upon them as surely as it was upon Solomon.
The verse is of importance to all God's people in this age: in the business God desires appointed men to carry on for the safety and prosperity of His kingdom, He does not join together scattered elements without genuine experience and without promise of dependable character. Rather He entrusts responsibility for molding a nation for most solemn, sacred service to those fitted to represent Him in an uplifted, purified state.