1 Kings 2:2

I go the way of all the earth
A path which is the path of death ^F15, which all pass in, kings and peasants, high and low, rich and poor, great and small, good and bad; none are exempted, all must die, and do; it is the appointment of God, a decree which can never be reversed; all experience confirms it: this same phrase is used by Joshua, from whom David seems to have borrowed it, and shows that that book was written in his days, ( Joshua 23:14 ) ;

be thou strong therefore;
not discouraged at my death, being a common thing, and to be expected; nor at being left alone, the Lord can give thee wisdom and counsel, assistance and strength, protection, and defence; take heart therefore, and be of good courage:

and show thyself a man;
in wisdom and understanding, and in fortitude of mind, though so young a man; which were necessary for the government of so great a people, and to guard against the secret intrigues of some, and the open flatteries of others, and the fear of attempts against his person and government, and the temptations he might be liable to, to do wrong things; and especially they were necessary to enable him to keep the commands of God, as follows; which required great strength of mind and of grace, considering the corruptions of nature, the temptations of Satan, and the snares of men; see ( Joshua 1:7 ) .