The law
towrah (to-raw')
a precept or statute, especially the Decalogue or Pentateuch -- law.
of his God
'elohiym (el-o-heem')
angels, exceeding, God (gods)(-dess, -ly), (very) great, judges, mighty.
is in his heart
leb (labe)
the heart; also used (figuratively) very widely for the feelings, the will and even the intellect
none of his steps
'ashur (aw-shoor')
a step -- going, step.
shall slide
ma`ad (maw-ad')
to waver -- make to shake, slide, slip.
