The pressure on saints to rest, somehow (6)
I believe the answer is:
stress
'the pressure' is the definition.
(I've seen this in another clue)
'saints to rest somehow' is the wordplay.
'saints' becomes 'ss' (an abbreviation for saint written twice).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'somehow' indicates anagramming the letters.
'rest' with letters rearranged gives 'stre'.
'ss' put after 'stre' is 'STRESS'.
'on' is the link.
(Other definitions for stress that I've seen before include "Emphasis: result often of being under pressure" , "Emphasise the strain" , "Underline - tension" , "why off work?" , "Draw attention to" .)