I love this poem by George Herbert, 17th century poet and clergyman. There are so many wonderful analogies in it. Prayer as a plummet sounding the depths of God's love, a siege engine against the Almighty like the widow "crying out to God day and night" (Luke 18:6).

Prayer (I) by George Herbert (1593-1633) 

Prayer the church's banquet, angel's age,  
God's breath in man returning to his birth,  
The soul in paraphrase, heart in pilgrimage,  
The Christian plummet1 sounding heav'n and earth  
Engine2 against th' Almighty, sinner's tow'r,  
Reversed thunder, Christ-side-piercing spear,  
The six-days world transposing in an hour,  
A kind of tune, which all things hear and fear;  
Softness, and peace, and joy, and love, and bliss,  
Exalted manna, gladness of the best,  
Heaven in ordinary, man well drest,  
The milky way, the bird of Paradise,  
Church-bells beyond the stars heard, the soul's blood,  
The land of spices; something understood. 

1 A piece of lead attached to a line, used in sounding the depth of water, a plumb bob or a plumb line. -- Wiktionary 

2 "'Engine against th' Almighty–' writing in the early 17th century, Herbert wasn't talking about a diesel engine, or even a steam engine. The engine in this line is a siege engine. Prayer is laying siege to God." -- Daniel Stanley https://cultusandculture.com/2016/07/28/engine-against-th-almighty/  

Image by Sheila Bair