Romans 9:19 - 24 speak to this situation, though some may not like the implications of it, which again, makes me grateful for the Grace of God!
19 Thou wilt say then unto me, Why doth he yet find fault? For who hath resisted his will?
20 Nay but, O man, who art thou that repliest against God? Shall the thing formed say to him that formed it, Why hast thou made me thus?
21 Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
22 What if God, willing to shew his wrath, and to make his power known, endured with much longsuffering the vessels of wrath fitted to destruction:
23 And that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory,
24 Even us, whom he hath called, not of the Jews only, but also of the Gentiles?
Timmy,
For the question as to how one can believe that GOD is JUST and RIGHTEOUS in ALL HE does, refer to verses 23 & 24 specifically, then read the rest of the chapter as St. Paul ties the Sovereignty of GOD into the SALVATION made available to the Gentiles, by faith!!