The king
melek (meh'-lek)
a king -- king, royal.
that faithfully
'emeth (eh'-meth)
stability; (figuratively) certainty, truth, trustworthiness -- assured(-ly), establishment, faithful, right, sure, true (-ly, -th), verity.
judgeth
shaphat (shaw-fat')
to judge, i.e. pronounce sentence (for or against); by implication, to vindicate or punish; by extenssion, to govern; passively, to litigate
the poor
dal (dal)
dangling, i.e. (by implication) weak or thin -- lean, needy, poor (man), weaker.
his throne
kicce' (kis-say')
covered, i.e. a throne (as canopied) -- seat, stool, throne.
shall be established
kuwn (koon)
to be erect (i.e. stand perpendicular); hence (causatively) to set up, in a great variety of applications
for ever
`ad (ad)
a (peremptory) terminus, i.e. (by implication) duration, in the sense of advance or perpetuity (substantially as a noun, either with or without a preposition)