Psalms 66:16

all ye that fear God The whole drift of the Ps., especially Psalms 66:1; Psalms 66:5; Psalms 66:8, is in favour of extending the phrase to include all who fear God wherever they are to be found, whether Israelites, or non-Israelites who have been won to worship Him by the sight of His works, rather than of limiting it to Israel, or an inner circle of the faithful in Israel.

what he hath done for my soul What he did for me when my very life was in danger. If Hezekiah is the speaker, he may be thinking at once of his own life (Isaiah 38:17) and of the life of the nation whose representative he was. He had prayed for both (Isaiah 37:15 ff; Isaiah 38:2); and the preservation of the one was a pledge of the preservation of the other (Isaiah 38:6).