Since the psalms were sung in the Temple by the Levites and combined poetry and prayer, it is not surprising that many deal with faith in God. As noted above, a key observation of the psalmists is that humans cannot confide in mortals whose days “are as grass.” One of the most important messages in Psalms is never to give up and rely primarily on God, not on man. In fact, one should not be surprised if the so called friends he turns to when in trouble do not come to his assistance. It is foolish for one to confide in people who are filled with deceit and whose days are numbered. Those who place their trust in God, however, will see that justice ultimately prevails.
Put not your trust in princes, nor in the son of man, in whom there is no help (Psalm 146:3).
I will lift up my eyes to the mountains, from where comes my help. My help comes from the Lord who made heaven and earth. He will not let your foot slip; He who watches over you does not slumber (Psalm 121: 1-3).
The Lord is my strength and my shield; my heart trusts in Him, and I was helped. My heart was overjoyed and I will give praise to him with my song. The Lord is the strength of his people, a fortress of salvation for his anointed one. Save your people and bless your inheritance; be their shepherd and elevate them forever (Psalm 28: 7-9).
As for man, his days are as grass: as a flower of the field, so he sprouts. For if a wind passes over it, it is gone; and the place thereof shall know it no more. But the kindness of the Lord is from everlasting to everlasting upon those that fear him, and His righteousness unto children's children (Psalm 103: 15-17).