When I was a lad (more years ago than I care to remember), and a STAB infanteer Private, the mission of the infantry was:
"To close with the enemy, observe him, and destroy him".
Many years later, when I had become a Principal Scientific Officer (imaginary equivalent rank of full Colonel, ferchrissake) with an MoD agency based on top of a hill somewhere in Kent, I saw a poster on a wall in the establishment giving what was then the mission of the infantry:
"To close with the enemy, and act in such a way as to bring about his defeat"
to which some wag had added in marker pen
"...if that's OK with everyone and nobody gets hurt".