In the corporate world, delegation of authority is part and parcel of getting the business to run smoothly for better profits. In the biblical context, the instances of delegation of authority we see in today's readings are more of a 'commissioning'. The significance is even greater if one thinks of it as a 'missioning' - a venturing on a mission, a mission to establish that "You, Lord, are the ruler of all" (1 Chron. 29:12). The 'profits' that accrue are not for one's self-gain, but for God's glory.
Therefore the dying David tells his son, Solomon, how to conduct himself - according to the 'injunctions of the Lord'. The noteworthy sequel to this is "that so you may be successful in all you do, so that the Lord may fulfil the promise He made me". David's and Solomon's roles were not to gain anything for themselves as much as to ensure, by their sovereignty, the working of God's plans for His people.
Similarly, Jesus in His time, 'missions' the Twelve. The instructions He gives are very specific, to the extent of telling them what to do when rejected. Basically, though, they were charged with living in simplicity, with nothing but confidence in God's providence, preaching repentance all the while. Essentially, that was it - to ensure God's plans worked out. The spreading of Jesus' message was their responsibility as the Cross approached for Him.
Lord, today the Cross has come, but the 'mission' remains the same for us. Do we know what it is? Remind us Lord. Amen.