More missions mandates from Psalms 9:
But the Lord sits enthroned forever;
he has established his throne for justice,
8 and he judges the world with righteousness;
he judges the peoples with uprightness.
9 The Lord is a stronghold for the oppressed,
a stronghold in times of trouble.
10 And those who know your name put their trust in you,
for you, O Lord, have not forsaken those who seek you.
11 Sing praises to the Lord, who sits enthroned in Zion!
Tell among the peoples his deeds!
12 For he who avenges blood is mindful of them;
he does not forget the cry of the afflicted.
13 Be gracious to me, O Lord!
See my affliction from those who hate me,
O you who lift me up from the gates of death,
14 that I may recount all your praises,
that in the gates of the daughter of Zion
I may rejoice in your salvation.
15 The nations have sunk in the pit that they made;
in the net that they hid, their own foot has been caught.
16 The Lord has made himself known; he has executed judgment;
the wicked are snared in the work of their own hands. Higgaion.  Selah
17 The wicked shall return to Sheol,
all the nations that forget God.
18 For the needy shall not always be forgotten,
and the hope of the poor shall not perish forever.
19 Arise, O Lord! Let not man prevail;
let the nations be judged before you!
20 Put them in fear, O Lord!
Let the nations know that they are but men!
When we have received any special good thing from the Lord, it is well, according as we have opportunities, to tell others of it. When the woman who had lost one of her ten pieces of silver, found the missing portion of her money, she gathered her neighbours and her friends together, saying, “Rejoice with me, for I have found the piece which I had lost.” We may do the same; we may tell friends and relations that we have received such-and-such a blessing, and that we trace it directly to the hand of God. Why have we not already done this? Is there a lurking unbelief as to whether it really came from God; or are we ashamed to own it before those who are perhaps accustomed to laugh at such things? Who knows so much of the marvellous works of God as his own people; if they be silent, how can we expect the world to see what he has done? Let us not be ashamed to glorify God, by telling what we know and feel he has done; let us watch our opportunity to bring out distinctly the fact of his acting; let us feel delighted at having an opportunity, from our own experience, of telling what must turn to his praise; and them that honour God, God will honour in turn; if we be willing to talk of his deeds, he will give us enough to talk about. P. B. Power, in ‘I Wills’ of the Psalms.