You must use double quotes to continue an authorization ID across more than one line within a QMF linear procedure. All continuation lines must have a plus sign (+) in column one:
PROC Test_Connect MODIFIED LINE 1 CONNECT "A234567890123456789012345678901234567890123456789012345678901234567890 +1234567890123456789012345678901234567890123456789012345678" (PASSWORD=XYZ)