Muslims and Jews deny that God has a son. Do we have sufficient evidence in Old Testament to prove that God has a son?
Who hath ascended up into heaven, or descended? who hath gathered the wind in his fists? who hath bound the waters in a garment? *who hath established all the ends of the earth? what is his name, and what is his son’s name*, if thou canst tell? Pro 30:4 (Emphasis by me)
The above verse is talking about God (who has established all ends of the earth) and the says He has a son.
I will declare the decree: the Lord hath said unto me, Thou art my Son; this day have I begotten thee.
Kiss l the Son, lest he be angry, and ye perish from the way, when his wrath is kindled but a little. Blessed are all they that put their trust in him. Psa 2: 7, 12.
In verse 7 we that God declares someone as His son. Also this son cannot be a human or created being as we see in verse 12 that we are asked to trust in the son. Throughout Psalms we are asked to put our trust in God and not in man. Psalms 2.12 won’t contradict all other verses in Psalms which is asking us to put our Trust in God alone. So the son in verse 7 must be God.