Hi Paradoxe –
This is from the Hebrew Scriptures.
You have to read it in the context of the narrative.
Balac, the King of Moab, sends for Balaam to curse Israel. Balaam does not curse Isreal, but Balaam blesses her. Balac berates Balaam for not cursing Isreal, and that's when Balaam makes his reply:
God is not a man (like Balac), that he should lie ... " and finishes: "... I was brought to bless, the blessing I am not able to hinder."
This is because God has blessed Isreal, and will not lie nor go back on His word, as man does.
You are admitting that god is not a man !
The Doctrine of the Trinity is founded on the Hebrew understanding of God, and the data contained in the New Testament of Christ's declaration of His own Divine nature, and that the Holy Spirit as 'another' (cf John 14:17, 15:26, 16:13).