'Suffer' is Latin for 'carry from below' — from 'sub-' + 'ferre' (to bear). Enduring a weight placed on you.
To experience or be subjected to something bad or unpleasant; to tolerate or endure; (archaic) to allow or permit.
From Old French 'sofrir' (to endure, to bear, to allow), from Latin 'sufferre' (to bear, undergo, endure, sustain, carry from below), built from 'sub-' (under, from below — expressing support as much as subordination) + 'ferre' (to bear, to carry, to bring), from PIE *bher- (to carry, to bear a burden, to give birth). The root *bher- is one of the great productive roots of Indo-European: it underlies 'bear' (the verb), 'birth' (carrying to term), 'burden' (that which is borne), Latin 'ferre' (carry) — giving 'fertile' (fruit-bearing), 'conference' (carrying ideas together), 'transfer,' 'prefer,' 'defer,' and 'offer' — and Greek 'pherein' (to carry), giving 'metaphor' (carrying meaning across). The literal image of 'suffer' is muscular
The King James Bible's famous line 'Suffer the little children to come unto me' uses 'suffer' in its older sense of 'allow' or 'permit,' not 'cause pain to.' This sense — carrying or bearing with patience, hence tolerating, hence permitting — shows the full semantic arc from physical carrying to abstract permission. The 'allow' sense is now archaic in everyday English but