# the eyes of Yahweh run everywhere throughout the whole earth

"Yahweh sees what is happening all over the earth" 

# so that he might show himself strong on behalf of

"and Yahweh protects with his strength" or "so that he may show his strength by protecting" 

# those whose hearts are perfect toward him

"those who are completely committed to following him" or "those who are completely devoted to following him"