Luke 18:1

And he spoke a parable to them, that they ought always to pray, and not to become weary,

Philippians 4:6

Be anxious about nothing, but in every thing, by prayer and supplication with thanksgiving, let your requests be made known to God:

Colossians 4:2

Persevere in prayer, and be watchful in the same with thanksgiving;

Treasury of Scripture Knowledge

Summary

Because he hath inclined his ear unto me, therefore will I call upon him as long as I live.

Bible References

Therefore

Luke 18:1
And he spoke a parable to them, that they ought always to pray, and not to become weary,
Philippians 4:6
Be anxious about nothing, but in every thing, by prayer and supplication with thanksgiving, let your requests be made known to God:
Colossians 4:2
Persevere in prayer, and be watchful in the same with thanksgiving;