Matthew 13:21
yet hath he no root in himself, and therefore is but for a short season; and when affliction cometh, or persecution on account of the word, he is as soon disgusted.
Luke 18:1
And He spake also a parable to them, to shew that men ought always to pray, and not to faint:
Acts 10:2
and one that feared God, with all his house; giving also much alms to the people, and praying to God continually.
Ephesians 6:18
praying at all seasons with all prayer and supplication in the Spirit, and watching thereunto with all perseverance, and intercession for all the saints;
1 Thessalonians 5:17
Pray continually.