by K.N. Stovra
Then you shall say to Pharaoh, `Thus says YHWH, "Israel is My son, My firstborn. So I said to you, `Let My son go that he may serve Me'; but you have refused to let him go." (Exodus 4:22-23).
In this passage YHWH identifies himself as the Father since Israel is here described as His son. This would otherwise make no sense if YHWH were a Triune God.