I fast twice in the week, I give tithes of all that I possess.

People's New Testament

18:12 I fast twice in the week. He enumerates his claims on God. He is very scrupulous about fasting and paying tithes (Le 27:30).

Wesley's Notes

18:12 I fast twice in the week - So did all the strict Pharisees: every Monday and Thursday. I give tithes of all that I possess - Many of them gave one full tenth of their income in tithes, and another tenth in alms. the sum of this plea is, I do no harm: I use all the means of grace: I do all the good I can.

Matthew Henry's Concise Commentary

18:9-14 This parable was to convince some who trusted in themselves that they were righteous, and despised others. God sees with what disposition and design we come to him in holy ordinances. What the Pharisee said, shows that he trusted to himself that he was righteous. We may suppose he was free from gross and scandalous sins. All this was very well and commendable. Miserable is the condition of those who come short of the righteousness of this Pharisee, yet he was not accepted; and why not? He went up to the temple to pray, but was full of himself and his own goodness; the favour and grace of God he did not think worth asking. Let us beware of presenting proud devotions to the Lord, and of despising others. The publican's address to God was full of humility, and of repentance for sin, and desire toward God. His prayer was short, but to the purpose; God be merciful to me a sinner. Blessed be God, that we have this short prayer upon record, as an answered prayer; and that we are sure that he who prayed it, went to his house justified; for so shall we be, if we pray it, as he did, through Jesus Christ. He owned himself a sinner by nature, by practice, guilty before God. He had no dependence but upon the mercy of God; upon that alone he relied. And God's glory is to resist the proud, and give grace to the humble. Justification is of God in Christ; therefore the self-condemned, and not the self-righteous, are justified before God.