明枪易躲,暗箭难防 meaning in English

It is easy to dodge an open spear thrust,but difficult to guard against an arrow in the dark.It is easy to parry a spear-thrust in the open,but hard to evade an arrow shot in the dark.It is easy to dodge a spear in the open,but hard to guard against an arrow shot from a hidden place.A visible spear is easily withstood,but an unseen arrow is hard to guard against.A spear openly discharged at you is easy to avoid,but it is difficult to guard against such as are discharged in secret.Better an open enemy than a false friend.