1)
Is the end of the verse connected to the beginning?
1.
Radak: Yes. Yisrael should trust in Hashem, for in all generations He helped them and was their shield. "Betach" is singular; it refers to the Klal.
2.
Malbim: Even though Elokeinu is in Shamayim, trust in Him, for He is our help and shield - a shield from affliction, and help against the oppressor.
