'Recommend' is literally placing something back into someone's hand — from Latin 'manus' (hand) + 'dare' (give).
To suggest something as worthy of acceptance, use, or consideration; to advise or counsel; to make something attractive or acceptable.
From Medieval Latin 'recommandāre' (to commend again to someone's attention, to entrust anew), from 're-' (again, back) + 'commendāre' (to entrust, to commit to someone's care, to recommend), itself an intensified form of 'mandāre' (to order, to entrust, to commit to hand), from 'manus' (hand) + 'dare' (to give). The PIE roots are *man- (hand) and *deh₃- (to give). To recommend is literally to place something back into another person's hand — to re-entrust it with a personal endorsement. The 'manus + dare' compound 'mandāre'
A 'letter of recommendation' is, etymologically, a letter that places you back into someone's hand — it re-entrusts you to a new authority with a personal endorsement. The recommender is saying: 'I held this person in my hand (my care), and I now place them in yours.' The metaphor of personal transfer is at the heart