Acts 10:34-35
34 Then Peter began to speak: "I now realize how true it is that God does not show favoritism NIV
35
35but accepts men from every nation who fear him and do what is right.
NIV

Romans 2:11
11 For God does not show favoritism.
NIV

Ephesians 6:9
9 And masters, treat your slaves in the same way. Do not threaten them, since you know that he who is both their Master and yours is in heaven, and there is no favoritism with him.
NIV

Colossians 3:25
25 Anyone who does wrong will be repaid for his wrong, and there is no favoritism.
NIV

1 Timothy 5:21
21 I charge you, in the sight of God and Christ Jesus and the elect angels, to keep these instructions without partiality, and to do nothing out of favoritism.
NIV

James 2:1
1 My brothers, as believers in our glorious Lord Jesus Christ, don't show favoritism. NIV
James 2:9
9 But if you show favoritism, you sin and are convicted by the law as lawbreakers. NIV

But still...

Ex 20:5-6
5You shall not bow down to them or worship them; for I, the LORD your God, am a jealous God, punishing the children for the sin of the fathers to the third and fourth generation of those who hate me,
6 but showing love to a thousand [ generations] of those who love me and keep my commandments.
NIV

Exodus 33:19
19 And the LORD said, "I will cause all my goodness to pass in front of you, and I will proclaim my name, the LORD, in your presence. I will have mercy on whom I will have mercy, and I will have compassion on whom I will have compassion. NIV

Rom 9:10-18
Not only that, but Rebekah's children had one and the same father, our father Isaac. 11Yet, before the twins were born or had done anything good or bad-in order that God's purpose in election might stand: 12not by works but by him who calls-she was told, "The older will serve the younger." 13Just as it is written: "Jacob I loved, but Esau I hated."
14What then shall we say? Is God unjust? Not at all! 15For he says to Moses,
"I will have mercy on whom I have mercy,
and I will have compassion on whom I have compassion."
16It does not, therefore, depend on man's desire or effort, but on God's mercy. 17For the Scripture says to Pharaoh: "I raised you up for this very purpose, that I might display my power in you and that my name might be proclaimed in all the earth." 18Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden.
NIV

God does not show favoritism, and yet he does make choices between and among people, based on his sovereign knowledge, power and authority. Even from a merely human point of view, it is impossible for a parent to treat two children exactly the same, because they are not exaclty the same, and do not react to the same treatment exactly the same way, so that the parent-child relationship is in every case unique. Every human, being unique, will have a unique relationship and potential in dealing with God. Sometimes that certainly can look like preferences, but it isn't favoritism, at least not with God.

Matt 5:43-48
You have heard that it was said, `Love your neighbor and hate your enemy.' 44But I tell you: Love your enemies and pray for those who persecute you, 45that you may be sons of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. 46If you love those who love you, what reward will you get? Are not even the tax collectors doing that? 47And if you greet only your brothers, what are you doing more than others? Do not even pagans do that? 48Be perfect, therefore, as your heavenly Father is perfect.
NIV

I always thought Peter was one of his favorites too.

Seems like Abraham got some pretty special treatment and David was a man after God's own heart. Soloman was blessed beyond imagination and wasn't John considered the apostle Jesus loved,