Cross reference
Philippians 2:18
18 And in the same way do you be glad and have a part in my joy.
James 1:2-4
2 Let it be all joy to you, my brothers, when you undergo tests of every sort;
3 Because you have the knowledge that the testing of your faith gives you the power of going on in hope;
4 But let this power have its full effect, so that you may be made complete, needing nothing.
Philippians 3:1
1 For the rest, my brothers, be glad in the Lord. Writing the same things to you is no trouble to me, and for you it is safe.
Philippians 4:4
4 Be glad in the Lord at all times: again I say, Be glad.
Ephesians 3:13
13 For this reason it is my prayer that you may not become feeble because of my troubles for you, which are your glory.