Question: Is there a contradiction in Genesis 4:4, 6:8; Proverbs 8:35, 18:22, Luke 1:30; which appear as favoritism from God); and Romans 2:11, 1 Timothy 5:21, and James 2:9; which say the Lord does not show favoritism and tells us not to show favoritism? This has been causing me to doubt.
Answer: These are not contradictions at all. Remember, God is not a respecter of persons. (Acts 10:34). He judges according to truth (Romans 2:2), and is a righteous judge (2 Timothy 4:8).
Back to Genesis 4:4. God did not respect Cain’s offering; because it was a self-righteous offering, produced by his own works and labor. Abel brought the blood offering of an animal sacrifice (Hebrews 10:4); which, in type, pointed to Calvary; where Christ would shed his own life and blood for the sins of the world (Ephesians 1:7). God had rejected their parent’s fig leaves; and Adam and Eve accepted the covering of skins that God provided through the shedding of the blood of innocent animals to obtain the skins. (Hebrews 9:22).
God would have been unjust to have accepted Cain’s sacrifice, which was of his own effort. This is exactly what the Scribes and Pharisees did, in trying to justify themselves with their own self-righteousness. (Luke 16:15 and 18:9).
"And he said unto them, Ye are they which justify yourselves before men; but God knoweth your hearts: for that which is highly esteemed among men is abomination in the sight of God." - Luke 16:15
"And he spake this parable unto certain which trusted in themselves that they were righteous, and despised others:" - Luke 18:9
And it is exactly what many are doing today by trusting their church membership, their popularity in the community, their baptism, confirmation, etc. All are rejected for salvation by the Lord, the Righteous Judge (Ephesians 2:8,9, Titus 3:5).
You cite Proverbs 8:35. Read also Verse 36, which says those that hate God love death. In Verse 35, God says that
"For whoso findeth me findeth life, and shall obtain favour of the LORD."
This is proof God is not a respecter of persons, but judges righteously. What would you think of God if He rewarded the wicked, and cursed the righteous? This is exactly what some have done, and still do today (James 2:1-4).
God denounces these acts, as stated in Isaiah 5:20,21,23,
“Woe unto them that call evil good, and good evil; that put darkness for light, and light for darkness; and put bitter for sweet, and sweet for bitter!” (20) “Woe unto them that are wise in their own eyes, and prudent in their own sight.” (21) “Which justify the wicked for reward, and take away the righteousness of the righteous from him!” (23)
“For there is no respect of persons with God.”
...is proved by John 3:16.
“For God so loved the world, that he gave his only begotten son, that whosoever believeth in him should not perish, but have everlasting life.”
John 3:36 shows God’s love and justice. God would be unjust if he let the unbeliever into Heaven and sent the believer to Hell. Such is not the case!
Concerning 1 Timothy 5:21, the principle is the same. Read all of Chapter 5. The instructions given were to be followed without showing any partiality whatsoever. James 2:9 is explained by the preceding verses. John 7:24 states,
“Judge not according to the appearance, but judge righteous judgment.”
Taking verses in their surrounding context can remove much doubt! Context! Context! Context!