A. Because prayer is the most important part of the thankfulness God requires of us.1 And also because God gives his grace and Holy Spirit only to those who pray continually and groan inwardly, asking God for these gifts and thanking him for them.2
Biblical References:
1 Ps. 50:14-15; 116:12-19; 1 Thess. 5:16-18
2 Matt. 7:7-8; Luke 11:9-13