Continue in prayer, and watch in the same with thanksgiving.
Devote yourselves to prayer, being watchful and thankful.
Continue steadfastly in prayer, being watchful in it with thanksgiving.
Continue earnestly in prayer, being vigilant in it with thanksgiving.
Devote yourselves to prayer with an alert mind and a thankful heart.
Devote yourselves to prayer, keeping alert in it with thanksgiving.
Continue steadfastly in prayer, watching in it with thanksgiving.
Persevere in prayer, with alert minds and thankful hearts.