The psalm for tomorrow’s Liturgy is Psalm 18, written by David when God saved him from the hand of Saul.  It begins “I love thee, O Lord, my strength.”  Here is Amy Carmichael’s commentary on this and the next verse.

Let us pray for one another that we may not go into caves. [cf. Ps 142]  Any one of us might do it at any moment, but for the grace of God.  The heading of this Psalm says that it is the Song which David spoke to the Lord . . . when he was delivered from his enemies—those enemies who had driven him into the cave.

There are many caves besides the cave of selfishness and self-love . . .; but whatever our cave is, the moment we get out, the devil is sure to tell us we shall soon be back again, and so the second verse in the LXX is delightful: ‘The Lord is my firm support’.

Is that not just what we want?  We know our weakness, we have proved it many a time; but we need not fall, for ‘the Lord is our firm support’.  I have noticed that some of the happiest people are not by nature the strongest, but they are those who love the Lord their Strength with a confident, joyful love; and they are not constantly thinking of themselves and their weakness, nor do they ever dream of not enjoying what He gives them to do, for ‘the joy of the Lord is [their] strength’, and their Lord is their firm support.”