Hi, well my dad helped me find sent strengthen and standing so here is what I learned. It is in 1 Thessalonians 3:2-5 which says, we sent timothy, who is our brother and God‘s fellow worker in spreading the gospel of Christ, to strenthen and encourage you in your faith, so that no one would be unsettled by these trials. You know quite well that we were destined for them. In fact, when we were with you, we kept telling you that we would be persecuted. And it turned out that way, as you well know. For this reason, when I could stand it no longer, I sent to find out about you faith. I was afraid that in some way the tempter might have tempted you and our efforts might have been useless.
So Paul sent timothy to strengthen the church and make sure they were still standing.
Another thing to learn is that the gospel strengthens our minds and our hearts.
When Paul sent Timothy to bring the gospel we can see a picture of Jesus in him like this God (or Paul) sent his one and only son (or Timothy) to come to this earth (or the church in Thessalonica) to die for us (or bring the gospel) so Paul sent Timothy to the church to send the gospel and to strengthen us.