Passage
From the height of the day I shall fear: but I will trust in thee.
Psalms 55:4 (DRB)
Nearby Context
Psalms 55:2 Have mercy on me, O God, for man hath trodden me under foot; all the day long he hath afflicted me fighting against me.
Psalms 55:3 My enemies have trodden on me all the day long; for they are many that make war against me.
Psalms 55:4 From the height of the day I shall fear: but I will trust in thee.
Psalms 55:5 In God I will praise my words, in God I have put my trust: I will not fear what flesh can do against me.
Psalms 55:6 All the day long they detested my words: all their thoughts were against me unto evil.
Study Lenses
The verse centers on "height", "shall", "fear", "trust", and "thee". It is saying that the verse draws attention to "height" and "shall", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 3's "My enemies have trodden on me all..." into verse 5's "In God I will praise my words...", so "height" and "shall" belong inside that flow. In Psalms context, the local focus is worship, trust, the LORD's kingship, and covenant mercy.
A plain takeaway is to answer the verse's own emphasis on "height" and "shall" with trust shaped by these words, not by a vague optimism outside the passage.