Job 16:19

My witness is in heaven - That is, I can appeal to God for my sincerity. He is my witness; and he will bear record for me. This is an evidence of returning confidence in God - to which Job always returns even after the most passionate and irreverent expressions. Such is his real trust in God, that though he is betrayed at times into expressions of impatience and irreverence, yet he is sure to return to calmer views, and to show that he has true confidence in the Most High. The strength, the power, and the point of his expressions of passion and impatience are against his “friends;” but they “sometimes” terminate on God, as if even he was leagued with them against him. But he still had “permanent” or “abiding” confidence in God.

My record is on high - Margin “in the high places.” It means, in heaven. Luther renders this, und der mich kennet, ist in der Hohe - and he who knows me is on high. The Hebrew is שׂהדי śâhêdı̂y - “my witness;” properly an eye witness. The meaning is, that he could appeal to God as a witness of his sincerity.